criyle/codenet-compile-errors huggingface dataset:
Language: C++

#include "iostream"
#include "climits"
#include "list"
#include "queue"
#include "stack"
#include "set"
#include "functional"
#include "algorithm"
#include "string"
#include "map"
#include "unordered_map"
#include "unordered_set"
#include "iomanip"
#include "cmath"
#include "random"
#include "bitset"
#include "cstdio"
#include "numeric"
#include "cassert"
#include "ctime"

using namespace std;

constexpr long long int MOD = 1000000007;
//constexpr int MOD = 1000000007;
//constexpr int MOD = 998244353;
//constexpr long long int MOD = 998244353;
constexpr double EPS = 1e-8;

//int N, M, K, H, W, L, R;
long long int N, M, K, H, W, L, R;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	cin>>N;
	if(N%3==0){
		vector<string>ans(3,string(3,'.'));
		ans[0]="aab";
		ans[1]="d.b";
		ans[2]="dcc";
		for(int i=0;i<N;i++){
			for(int j=0;j<N;j++){
				cout<<ans[i%3][j%3];
			}
			cout<<endl;
		}
		return 0;
	}
	else if(N%4==0){
		vector<string>ans(4,string(4,'.'));
		ans[0]="abcc";
		ans[1]="abdd";
		ans[2]="eegh";
		ans[3]="ffgh";
		for(int i=0;i<N;i++){
			for(int j=0;j<N;j++){
				cout<<ans[i%4][j%4];
			}
			cout<<endl;
		}
		return 0;
	}
	for(int i=N;i>=0;i-=9){
		vector<string>ans3(3,string(3,'.'));
		ans3[0]="aa.";
		ans3[1]="..b";
		ans3[2]="..b";
		vector<string>ans4(4,string(4,'.'));
		ans4[0]="abcc";
		ans4[1]="abdd";
		ans4[2]="eegh";
		ans4[3]="ffgh";
		vector<string>ret(N,string(N,'.'));
		if(i%4==0){
			int dif=N-i;
			for(int j=0;j<dif;j++){
				for(int k=j/9*9;k<j/9*9+9;k++){
					ret[j][k]=ans3[j%3][k%3];
				}
			}
			for(int j=0;j<i;j++){
				for(int k=j/4*4;k<j/4*4+4;k++){
					ret[dif+j][dif+k]=ans4[j%4][k%4];
				}
			}
			for(auto j:ret){
				cout<<j<<endl;
			}
			return 0;
		}
	}
	for(int i=N;i>=0;i==6){
		vector<string>ans6(6,string(6,'.'));
		ans6[0]="ee.aab";
		ans6[1]="..fc.b";
		ans6[2]="..fcdd";
		ans6[0]="aabee.";
		ans6[1]="c.b..f";
		ans6[2]="cdd..f";
		vector<string>ans4(4,string(4,'.'));
		ans4[0]="abcc";
		ans4[1]="abdd";
		ans4[2]="eegh";
		ans4[3]="ffgh";
		vector<string>ret(N,string(N,'.'));
		if(i%4==0){
			int dif=N-i;
			for(int j=0;j<dif;j++){
				for(int k=j/6*6;k<j/6*6+6;k++){
					ret[j][k]=ans3[j%6][k%6];
				}
			}
			for(int j=0;j<i;j++){
				for(int k=j/4*4;k<j/4*4+4;k++){
					ret[dif+j][dif+k]=ans4[j%4][k%4];
				}
			}
			for(auto j:ret){
				cout<<j<<endl;
			}
			return 0;
		}
	}
	if(N>=36){
		cout<<-1<<endl;
		return 0;
	}
	cout<<-1<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:112:51: error: 'ans3' was not declared in this scope; did you mean 'ans4'?
  112 |                                         ret[j][k]=ans3[j%6][k%6];
      |                                                   ^~~~
      |                                                   ans4
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  int M = N;
  while (M%2==0) M/=2;
  if (N%3==0){
    vector<string> S(3);
    S[0] = "aad";
    S[1] = "b.d";
    S[2] = "bcc";
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N/3; j++){
        cout << S[i%3];
      }
      cout << endl;
    }
  } else if (N%5==0){
    vector<string> S(5);
    S[0] = "ahhgg";
    S[1] = "a.iif";
    S[2] = "bj..f";
    S[3] = "bj..e";
    S[4] = "ccdde";
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N/5; j++){
        cout << S[i%5];
      }
      cout << endl;
    }
  } else if (N%4==0){
    vector<string> S(4);
    S[0] = "aabc";
    S[1] = "ddbc";
    S[2] = "efgg";
    S[3] = "efhh";
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N/4; j++){
        cout << S[i%4];
      }
      cout << endl;
    }
  } else if (N%7==0){
    vector<string> S(7);
    S[0] = "aadaade";
    S[1] = "b.db.de";
    S[2] = "bccbccf";
    S[3] = "aadaadf";
    S[4] = "b.db.de";
    S[5] = "bccbcce";
    S[6] = "eeffee.";
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N/7; j++){
        cout << S[i%7];
      }
      cout << endl;
    }
  } else if (N==2){
    cout << -1;
  } else {
    cout << 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:63:2: error: expected '}' at end of input
   63 | }
      |  ^
a.cc:3:11: note: to match this '{'
    3 | int main(){
      |           ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    if(n==2){
        cout << -1;
        return 0;
    }
    char a[n][n];
    int i,j;
    if(n%3==0){
    for(i=0;i<n;i=i+3){
        for(j=0;j<n;j=j+3){
            a[i][j]='a';
            a[i][j+1]='a';
            a[i][j+2]='d';
            a[i+1][j]='b';
            a[i+1][j+1]='.';
            a[i+1][j+2]='d';
            a[i+2][j]='b';
            a[i+2][j+1]='c';
            a[i+2][j+2]='c';
        }
    }
    }
    else if(n%2==0){
        int k=1;
        int l;
        for(i=0;i<n;i=i+2){
            l=k;
            for(j=0;j<n;j=j+2){
                if(k==1){
                    a[i][j]='c';
                    a[i][j+1]='c';
                    a[i+1][j]='d';
                    a[i+1][j+1]='d';
                    k=0;
                }
                else{
                    a[i][j]='a';
                    a[i][j+1]='b';
                    a[i+1][j]='a';
                    a[i+1][j+1]='b';
                    k=1;
                }
            }
            if(n%4==2){
                k=(k+1)%2;
            }
        }
    }
    else{
        for(i=0;i<n;i=i+2){
            for(j=0;j<n;j=j+2){
                a[i][j]='c';
                a[i][j+1]='c';
                a[i+1][j]='d';
                a[i+1][j+1]='d';
            }
        }
    }
    }
    else{
        cout << -1;
        return 0;
    }
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            cout << a[i][j];
        }
    cout << endl;
    }
}


Compiler output:
a.cc:64:5: error: expected unqualified-id before 'else'
   64 |     else{
      |     ^~~~
a.cc:68:5: error: expected unqualified-id before 'for'
   68 |     for(i=0;i<n;i++){
      |     ^~~
a.cc:68:13: error: 'i' does not name a type
   68 |     for(i=0;i<n;i++){
      |             ^
a.cc:68:17: error: 'i' does not name a type
   68 |     for(i=0;i<n;i++){
      |                 ^
a.cc:74:1: error: expected declaration before '}' token
   74 | }
      | ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    if(n==2){
        cout << -1;
        return 0;
    }
    char a[n][n];
    int i,j;
    if(n%3==0){
    for(i=0;i<n;i=i+3){
        for(j=0;j<n;j=j+3){
            a[i][j]='a';
            a[i][j+1]='a';
            a[i][j+2]='d';
            a[i+1][j]='b';
            a[i+1][j+1]='.';
            a[i+1][j+2]='d';
            a[i+2][j]='b';
            a[i+2][j+1]='c';
            a[i+2][j+2]='c';
        }
    }
    }
    else if(n%2==0){
        int k=1;
        int l;
        for(i=0;i<n;i=i+2){
            l=k;
            for(j=0;j<n;j=j+2){
                if(k==1){
                    a[i][j]='c';
                    a[i][j+1]='c';
                    a[i+1][j]='d';
                    a[i+1][j+1]='d';
                    k=0;
                }
                else{
                    a[i][j]='a';
                    a[i][j+1]='b';
                    a[i+1][j]='a';
                    a[i+1][j+1]='b';
                    k=1;
                }
            }
            if(n%4==2){
                k=(k+1)%2;
            }
        }
    else{
        for(i=0;i<n;i=i+2){
            for(j=0;j<n;j=j+2){
                a[i][j]='c';
                a[i][j+1]='c';
                a[i+1][j]='d';
                a[i+1][j+1]='d';
            }
        }
    }
    }
    else{
        cout << -1;
        return 0;
    }
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            cout << a[i][j];
        }
    cout << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:52:5: error: expected '}' before 'else'
   52 |     else{
      |     ^~~~
a.cc:27:20: note: to match this '{'
   27 |     else if(n%2==0){
      |                    ^
a.cc: At global scope:
a.cc:63:5: error: expected unqualified-id before 'else'
   63 |     else{
      |     ^~~~
a.cc:67:5: error: expected unqualified-id before 'for'
   67 |     for(i=0;i<n;i++){
      |     ^~~
a.cc:67:13: error: 'i' does not name a type
   67 |     for(i=0;i<n;i++){
      |             ^
a.cc:67:17: error: 'i' does not name a type
   67 |     for(i=0;i<n;i++){
      |                 ^
a.cc:73:1: error: expected declaration before '}' token
   73 | }
      | ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    if(n==2){
        cout << -1;
        return 0;
    }
    char a[n][n];
    int i,j;
    if(n%3==0){
    for(i=0;i<n;i=i+3){
        for(j=0;j<n;j=j+3){
            a[i][j]='a';
            a[i][j+1]='a';
            a[i][j+2]='d';
            a[i+1][j]='b';
            a[i+1][j+1]='.';
            a[i+1][j+2]='d';
            a[i+2][j]='b';
            a[i+2][j+1]='c';
            a[i+2][j+2]='c';
        }
    }
    }
    else if(n%2==0){
    if(k=1){
        for(i=0;i<n;i=i+2){
            for(j=0;j<n;j=j+2){
                a[i][j]='a';
                a[i][j+1]='b';
                a[i+1][j]='a';
                a[i+1][j+1]='b';
            }
        }
    }
    else{
        for(i=0;i<n;i=i+2){
            for(j=0;j<n;j=j+2){
                a[i][j]='c';
                a[i][j+1]='c';
                a[i+1][j]='d';
                a[i+1][j+1]='d';
            }
        }
    }
    }
    else{
        cout << -1;
        return 0;
    }
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            cout << a[i][j];
        }
    cout << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:28:8: error: 'k' was not declared in this scope
   28 |     if(k=1){
      |        ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  int M = N;
  while (M%2==0) M/=2;
  if (N%3==0){
    vector<string> S(3);
    S[0] = "aad";
    S[1] = "b.d";
    S[2] = "bcc";
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N/3; j++){
        cout << S[i%3];
      }
      cout << endl;
    }
  } else if (N%5==0){
    vector<string> S(5);
    S[0] = "ahhgg";
    S[1] = "a.iif";
    S[2] = "bj..f";
    S[3] = "bj..e";
    S[4] = "ccdde";
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N/5; j++){
        cout << S[i%5];
      }
      cout << endl;
    }
  } else if (N%4==0){
    vector<string> S(4);
    S[0] = "aabc";
    S[1] = "ddbc";
    S[2] = "efgg";
    S[3] = "efhh";
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N/4; j++){
        cout << S[i%4];
      }
      cout << endl;
    }
  } else if (N==2){
    cout << -1;
  } else {
    cout << 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:48:2: error: expected '}' at end of input
   48 | }
      |  ^
a.cc:3:11: note: to match this '{'
    3 | int main(){
      |           ^
Language: C++

#include <iostream>
#include <algorithm>
#include <iomanip>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <vector>
#include <string>
#include <queue>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <bitset>

using namespace std;
typedef long long ll;

string S3[] = {
	"abb",
	"a.c",
	"ddc"
};
string S4[] = {
	"abcc",
	"abdd",
	"eefg",
	"hhfg"
};
string S5[] = {
	"aabbc",
	"d..ec",
	"d..ef",
	"ghh.f",
	"giijj"
};

int main() {
	int N; cin >> N;
	if (N % 3 == 0) {
		for (int i = 0; i < N; i++) {
			for (int j = 0; j < N; j++) {
				cout << S3[i % 3][j % 3];
			}
			cout << endl;
		}
	}
	else {
		int n = 0, m = 0;
		for (int i = 0; i < N; i++) {
			if ((N - 4 * i) % 5 == 0) {
				n = i;
				m = (N - 4 * n) / 5;
				break;
			}
		}

		if (n == 0 && m == 0) { cout << -1 << endl; return 0; }

		string* S = new string[N];
		for (int i = 0; i < N; i++) {
			for (int j = 0; j < N; j++) {
				S[i].push_back('.');
			}
		}

		for (int i = 0; i < n; i++) {
			for (int p = 0; p < 4; p++) {
				for (int q = 0; q < 4; q++) {
					S[i * 4 + p][i * 4 + q] = S4[p][q];
				}
			}
		}
		for (int i = 0; i < m; i++) {
			for (int p = 0; p < 5; p++) {
				for (int q = 0; q < 5; q++) {
					S[n * 4 + i * 5 + p][n * 4 + i * 5 + q] = S5[p][q];
				}
			}
		}
		for (int i = 0; i < N; i++) {
			cout << S[i] << endl;
		}
	}
	else {
		cout << -1 << endl;
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:86:9: error: 'else' without a previous 'if'
   86 |         else {
      |         ^~~~
Language: C++

-1#include <bits/stdc++.h>

using namespace std;
using ll=long long;

int main(){
    int n;
    cin>>n;
    if(n%3==0){
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                if(i%3==0){
                    if(j%3==2)cout<<'.';
                    else cout<<'a';
                }
                else{
                    if(j%3==2)cout<<'a';
                    else cout<<'.';
                }
            }
            cout<<"\n";
        }
    }
    return 0;
}


Compiler output:
a.cc:1:3: error: stray '#' in program
    1 | -1#include <bits/stdc++.h>
      |   ^
a.cc:1:1: error: expected unqualified-id before '-' token
    1 | -1#include <bits/stdc++.h>
      | ^
a.cc: In function 'int main()':
a.cc:8:5: error: 'cin' was not declared in this scope
    8 |     cin>>n;
      |     ^~~
a.cc:13:31: error: 'cout' was not declared in this scope
   13 |                     if(j%3==2)cout<<'.';
      |                               ^~~~
a.cc:14:26: error: 'cout' was not declared in this scope
   14 |                     else cout<<'a';
      |                          ^~~~
a.cc:17:31: error: 'cout' was not declared in this scope
   17 |                     if(j%3==2)cout<<'a';
      |                               ^~~~
a.cc:18:26: error: 'cout' was not declared in this scope
   18 |                     else cout<<'.';
      |                          ^~~~
a.cc:21:13: error: 'cout' was not declared in this scope
   21 |             cout<<"\n";
      |             ^~~~
Language: C++



int main(){
    int n;
    cin >> n;
  cout << -1 << endl;
  return 0;
    
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:5: error: 'cin' was not declared in this scope
    5 |     cin >> n;
      |     ^~~
a.cc:6:3: error: 'cout' was not declared in this scope
    6 |   cout << -1 << endl;
      |   ^~~~
a.cc:6:17: error: 'endl' was not declared in this scope
    6 |   cout << -1 << endl;
      |                 ^~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  int M = N;
  while (M%2==0) M/=2;
  if (N%3==0){
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N; j++){
        if (i%3==0 && j%3<2){
          cout << 'a';
        } else if (j%3==0){
          cout << 'b';
        } else if (i%3==2){
          cout << 'c';
        } else if (j%3==2){
          cout << 'd';
        } else {
          cout << '.';
        }
      }
      cout << endl;
    }
  } else {
    if (M==1){
      cout << 0;
    else {
      cout << 0;
    }
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:28:5: error: expected '}' before 'else'
   28 |     else {
      |     ^~~~
a.cc:26:14: note: to match this '{'
   26 |     if (M==1){
      |              ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    if(n%3!=0){
        cout << -1;
        return 0;
    }
    char a[n][n];
    int i,j;
    for(i=0;i<n;i=i+3){
        for(j=0;j<n;j=j+3){
        char a[i][j]='a';
        char a[i][j+1]='a';
        char a[i][j+2]='d';
        char a[i+1][j]='b';
        char a[i+1][j+1]='.';
        char a[i+1][j+2]='d';
        char a[i+2][j]='b';
        char a[i+2][j+1]='c';
        char a[i+2][j+2]='c';
        }
    }
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            cout << a[i][j];
        }
    cout << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:22: error: array must be initialized with a brace-enclosed initializer
   14 |         char a[i][j]='a';
      |                      ^~~
a.cc:15:14: error: conflicting declaration 'char a [i][(j + 1)]'
   15 |         char a[i][j+1]='a';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:16:14: error: conflicting declaration 'char a [i][(j + 2)]'
   16 |         char a[i][j+2]='d';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:17:14: error: conflicting declaration 'char a [(i + 1)][j]'
   17 |         char a[i+1][j]='b';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:18:14: error: conflicting declaration 'char a [(i + 1)][(j + 1)]'
   18 |         char a[i+1][j+1]='.';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:19:14: error: conflicting declaration 'char a [(i + 1)][(j + 2)]'
   19 |         char a[i+1][j+2]='d';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:20:14: error: conflicting declaration 'char a [(i + 2)][j]'
   20 |         char a[i+2][j]='b';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:21:14: error: conflicting declaration 'char a [(i + 2)][(j + 1)]'
   21 |         char a[i+2][j+1]='c';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:22:14: error: conflicting declaration 'char a [(i + 2)][(j + 2)]'
   22 |         char a[i+2][j+2]='c';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  if (N%3==0){
    for (int i = 0; i < N; i++){
      for (int j = 0; j < N; j++){
        if (i%3=2 && j%3<2){
          cout << 'a';
        } else if (j%3==0){
          cout << 'b';
        } else if (i%3==2){
          cout << 'c';
        } else if (j%3==2){
          cout << 'd';
        } else {
          cout << ' ';
        }
      }
    }
  } else {
    cout << 0;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:14: error: lvalue required as left operand of assignment
    9 |         if (i%3=2 && j%3<2){
      |             ~^~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    if(n%3!=0){
        cout << -1;
        return 0;
    }
    char a[n][n];
    int i,j;
    for(i=0;i<n;i=i+3){
        for(j=0;j<n;j=j+3){
        char a[i][j]='a';
        char a[i][j+1]='a';
        char a[i][j+2]='d';
        char a[i][j]='b';
        char a[i+1][j+1]='.';
        char a[i+1][j+2]='d';
        char a[i+2][j]='b';
        char a[i+2][j+1]='c';
        char a[i+2][j+2]='c';
        }
    }
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            cout << a[i][j];
        }
    cout << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:22: error: array must be initialized with a brace-enclosed initializer
   14 |         char a[i][j]='a';
      |                      ^~~
a.cc:15:14: error: conflicting declaration 'char a [i][(j + 1)]'
   15 |         char a[i][j+1]='a';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:16:14: error: conflicting declaration 'char a [i][(j + 2)]'
   16 |         char a[i][j+2]='d';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:17:14: error: redeclaration of 'char a [i][j]'
   17 |         char a[i][j]='b';
      |              ^
a.cc:14:14: note: 'char a [i][j]' previously declared here
   14 |         char a[i][j]='a';
      |              ^
a.cc:18:14: error: conflicting declaration 'char a [(i + 1)][(j + 1)]'
   18 |         char a[i+1][j+1]='.';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:19:14: error: conflicting declaration 'char a [(i + 1)][(j + 2)]'
   19 |         char a[i+1][j+2]='d';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:20:14: error: conflicting declaration 'char a [(i + 2)][j]'
   20 |         char a[i+2][j]='b';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:21:14: error: conflicting declaration 'char a [(i + 2)][(j + 1)]'
   21 |         char a[i+2][j+1]='c';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
a.cc:22:14: error: conflicting declaration 'char a [(i + 2)][(j + 2)]'
   22 |         char a[i+2][j+2]='c';
      |              ^
a.cc:14:14: note: previous declaration as 'char a [i][j]'
   14 |         char a[i][j]='a';
      |              ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    if(n%3!=0){
        cout << -1;
        return 0;
    }
    char a[n][n];
    for(i=0;i<n;i=i+3){
        for(j=0;j<n;j=j+3){
        char a[i][j]='a';
        char a[i][j+1]='a';
        char a[i][j+2]='d';
        char a[i][j]='b';
        char a[i+1][j+1]='.';
        char a[i+1][j+2]='d';
        char a[i+2][j]='b';
        char a[i+2][j+1]='c';
        char a[i+2][j+2]='c';
        }
    }
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            cout << a[i][j];
        }
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:11:9: error: 'i' was not declared in this scope
   11 |     for(i=0;i<n;i=i+3){
      |         ^
a.cc:12:13: error: 'j' was not declared in this scope
   12 |         for(j=0;j<n;j=j+3){
      |             ^
a.cc:24:9: error: 'i' was not declared in this scope
   24 |     for(i=0;i<n;i++){
      |         ^
a.cc:25:13: error: 'j' was not declared in this scope
   25 |         for(j=0;j<n;j++){
      |             ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long long LL;
typedef long double lb;
#define ri register int
const lb PI=3.141592653589793238462643383279;
const ll inf=1000000000000000000ll;
const int N=1000005,M=998244353;
long long qpow(long long a,long long b)
{
	long long s=a,ans=1;
	while(b)
	{
		if(b&1)
			ans=ans*s%M;
		b>>=1;
		s=s*s%M;
	}
	return ans;
}
int n,i,l,r;
char ans[1005][1005];
int main()
{
	scanf("%d",&n);
	if(n<=2||n==4||n==5||n%3!=0)
	{
		puts("-1");
		return 0;
	}
	for(i=1;i<=n;++i)
		for(j=1;j<=n;++j)
			ans[i][j]='.';
	if(n%3==0)
		for(i=1;i<=n;i+=3)
			ans[i][i]=ans[i][i+1]=ans[i+1][i+2]=ans[i+2]=ans[i+2]='a';
	for(i=1;i<=n;++i)
		printf("%s\n",ans[i]+1);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:33:21: error: 'j' was not declared in this scope
   33 |                 for(j=1;j<=n;++j)
      |                     ^
a.cc:37:78: error: incompatible types in assignment of 'char' to 'char [1005]'
   37 |                         ans[i][i]=ans[i][i+1]=ans[i+1][i+2]=ans[i+2]=ans[i+2]='a';
      |                                                                      ~~~~~~~~^~~~
Language: C++

眠い、助けて

Compiler output:
a.cc:1:1: error: extended character 、 is not valid in an identifier
    1 | 眠い、助けて
      | ^
a.cc:1:1: error: '\U00007720\U00003044\U00003001\U000052a9\U00003051\U00003066' does not name a type
    1 | 眠い、助けて
      | ^~~~~~~~~~~~
Language: C++

const int MAXN = 5010;

int mod;

inline int Mod(int x) { return x >= mod ? x - mod : x; }
inline void Add(int &x, int y) { x += y, x -= x >= mod ? mod : 0; }

int f[MAXN][MAXN];
int g[MAXN][MAXN];
int S[MAXN * 2];

int main() {
    int n = ri; mod = ri;
    int N = (n + 1) / 2;

    f[0][0] = 1;
    for(int i = 1; i <= N; i++)
        for(int j = 0; j <= n; j++)
            for(int k = j; k <= n; k += i)
                Add(f[i][k], f[i - 1][j]);

    g[0][0] = 1;
    for(int i = N - 1; i >= 1; i--) {
        for(int j = 0; j <= n; j++) {
            if(i * j >= n) break;
            for(int k = i * j; i + k <= n; k++)
                if(i + k <= n)
                    Add(g[j + 1][k + i], g[j][k]);
        }
    }

    for(int i = 0; i <= n; i++)
        for(int j = 1; j <= n; j++)
            Add(g[i][j], g[i][j - 1]);
    for(int i = 1; i <= n; i++)
        for(int j = 0; j <= n; j++)
            Add(g[i][j], g[i - 1][j]);

    int n1 = N, n2 = N - 1;
    int res = 0;
    if(!(n & 1)) {
        for(int x = 1; x <= n; x++)
            for(int i = 0; i < x; i++)
                res = (res + 1LL * f[n1][i] * g[n - x][x - i - 1]) % mod;
    } else {
        for(int x = 1; x <= n; x++)
            for(int i = 0; i < x; i++)
                res = (res + 1LL * f[n2][i] * g[n - x][x - i - 1]) % mod;
    }
    printf("%d\n", res);
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:13: error: 'ri' was not declared in this scope
   13 |     int n = ri; mod = ri;
      |             ^~
a.cc:50:5: error: 'printf' was not declared in this scope
   50 |     printf("%d\n", res);
      |     ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | const int MAXN = 5010;
Language: C++

const int MAXN = 5010;
int mod;
inline int Mod(int x) { return x >= mod ? x - mod : x; }
inline void Add(int &x, int y) { x += y, x -= x >= mod ? mod : 0; }
int f[MAXN][MAXN];
int g[MAXN][MAXN];
int S[MAXN * 2];
int main() {
    int n,mod ;
    int N = (n + 1) / 2;
    f[0][0] = 1;
    for(int i = 1; i <= N; i++)
        for(int j = 0; j <= n; j++)
            for(int k = j; k <= n; k += i)
                Add(f[i][k], f[i - 1][j]);
    g[0][0] = 1;
    for(int i = N - 1; i >= 1; i--) {
        for(int j = 0; j <= n; j++) {
            if(i * j >= n) break;
            for(int k = i * j; i + k <= n; k++)
                if(i + k <= n)
                    Add(g[j + 1][k + i], g[j][k]);
        }
    }
    for(int i = 0; i <= n; i++)
        for(int j = 1; j <= n; j++)
            Add(g[i][j], g[i][j - 1]);
    for(int i = 1; i <= n; i++)
        for(int j = 0; j <= n; j++)
            Add(g[i][j], g[i - 1][j]);
    int n1 = N, n2 = N - 1;
    int res = 0;
    if(!(n & 1)) {
        for(int x = 1; x <= n; x++)
            for(int i = 0; i < x; i++)
                res = (res + 1LL * f[n1][i] * g[n - x][x - i - 1]) % mod;
    } else {
        for(int x = 1; x <= n; x++)
            for(int i = 0; i < x; i++)
                res = (res + 1LL * f[n2][i] * g[n - x][x - i - 1]) % mod;
    }
     printf("%d\n",res);
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:42:6: error: 'printf' was not declared in this scope
   42 |      printf("%d\n",res);
      |      ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | const int MAXN = 5010;
Language: C++

/*input
3 998244353
*/
#include <bits/stdc++.h>
#define pb push_back
#define all(a) a.begin(), a.end()
#define sz(a) (int)a.size()
#define x first
#define y second
#define debug(...) cout << "[" << #__VA_ARGS__ << ": " << __VA_ARGS__ << "]\n"
#define rd() abs((int)rng())
using namespace std;
typedef long long ll;
typedef double ld;
typedef pair<int, int>pii;
const int maxn = 5050;
const int mod = 1e9 + 7;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
int n, k, MOD, change[maxn];
void add(int &a, int b)
{
	a += b;
	if(a >= MOD)
		a -= MOD;
}
int dp[maxn][maxn];
int solve(int i, int opsbal)
{
	if(i == n - 2)
		return n - opsbal;
	int &ret = dp[i][opsbal];
	if(ret != -1)
		return ret;
	ret = 0;
	add(ret, solve(i + 1, opsbal));
	if(opsbal - change[i] + 1 <= n)
		add(ret, solve(i, opsbal - change[i] + 1));
	return ret;
}
int main()
{
	ios_base::sync_with_stdio(false), cin.tie(0);
	cin >> n >> MOD;
	
	k = (n - 1) / 2;
	change[0] = 0;
	for(int i = 1; i <= k; i++)
		change[i] = -i;
	if(n % 2 == 0)
		change[k + 1] = -k;
	int cur = -k;
	for(int i = k + (n % 2 == 0) + 1; i <= n; i++)
	{
		++cur;
		change[i] = cur;
	}

	sort(change, change + n + 1);

	memset(dp, -1, sizeof dp);
	if(n == 2)
		cout << 3 << "\n";
	else
	{
		ll ans = 0;
		for(int i = 0; i <= n - 1; i++)
			add(ans, solve(0, i));
		cout << ans << "\n";
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:67:29: error: cannot bind non-const lvalue reference of type 'int&' to a value of type 'll' {aka 'long long int'}
   67 |                         add(ans, solve(0, i));
      |                             ^~~
a.cc:20:15: note:   initializing argument 1 of 'void add(int&, int)'
   20 | void add(int &a, int b)
      |          ~~~~~^
Language: C++

#include<bits/stdc++.h>

using namespace std;

int N, K, mod;

int mul (int x, int y) {return 1LL * x * y % mod;}
void adto (int &x, int y) {x += y; if (x >= mod) x -= mod;}

void solve ()
{
    int dp[2][5009];
    for (int j=0; j<N; j++)
        dp[1][j] = 0;
    for (int j=0; j * K<N; j++)
        dp[1][j * K] = (N & 1 ? 1 : j + 1);
    for (int i=1; i<K; i++)
    {
        int nl = (i & 1) ^ 1;
        for (int j=0; j<=N; j++)
            dp[nl][j] = 0;
        for (int j=0; j<N; j++)
            if (dp[i & 1][j] > 0)
                for (int r=0; j + r * i < N; r++)
                    adto (dp[nl][j + r * i], mul (dp[i & 1][j], r + 1));
    }
    int ans = 0;
    for (int j=0; j<N; j++)
        adto (ans, dp[K & 1][j]);
    printf ("%d\n", ans);
}

int main ()
{
//freopen ("input", "r", stdin);
//freopen ("output", "w", stdout);

scanf ("%d %d", &N, &mod);
K = (N + 1) / 2;
solve ();
printf ("%d\n", ans);
return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:41:17: error: 'ans' was not declared in this scope; did you mean 'abs'?
   41 | printf ("%d\n", ans);
      |                 ^~~
      |                 abs
Language: C++

#ifdef DEBUG
#define _GLIBCXX_DEBUG
#endif
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
typedef long double ld;
typedef long long ll;
int n;
int mod;
inline int add(int a, int b) {
    int s = a + b;
    if (s >= mod) s -= mod;
    return s;
}
inline int mult(int a, int b) {
    return (1LL * a * b) % mod;
}
inline int sub(int a, int b) {
    int s = a - b;
    if (s < 0) s += mod;
    return s;
}
const int maxN = 5005;
ll dp[maxN][maxN];
void calc(int cnt, int at_most) {
    for (int i = 1; i < cnt; i++) {
        for (int sum = at_most; sum >= 0; sum--) {
            ll p0 = 0;
            ll p1 = 0;
            for (int new_last = 0; ; new_last++) {
                if (new_last * (cnt - i + 1) + sum > at_most) break;
                p0 += dp[new_last][sum];
                p1 += new_last * dp[new_last][sum];
                dp[new_last][sum + new_last] = ((new_last + 1) * p0) - p1) % mod;
                if (dp[new_last][sum + new_last] < 0) dp[new_last][sum + new_last] += mod;
            }
        }
    }
}
int c2[maxN];
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
//    freopen("input.txt", "r", stdin);
    cin >> n >> mod;
    for (int i = 0; i <= n + 1; i++) {
        c2[i] = ((1LL * i * (i - 1)) / 2) % mod;
    }
    if (n == 2) {
        cout << 3;
        return 0;
    }
    if (n % 2 == 1) {
        for (int last = 0; last <= n; last++) {
            dp[last][last] = 1;
        }
    }
    else {
        for (int last = 0; last <= n; last++) {
            dp[last][last] = last + 1;
        }
    }
    calc((n - 1) / 2, n);
    int ans = 0;
    for (int last = 0; last <= n; last++) {
        for (int sum = 0; sum + last <= n + 1; sum++) {
            if (dp[last][sum] == 0) continue;
            ans = add(ans, mult(dp[last][sum], c2[n - sum - last + 1]));

        }
    }
    cout << ans;
    return 0;
}

Compiler output:
a.cc: In function 'void calc(int, int)':
a.cc:36:74: error: expected ';' before ')' token
   36 |                 dp[new_last][sum + new_last] = ((new_last + 1) * p0) - p1) % mod;
      |                                                                          ^
      |                                                                          ;
Language: C++

#include<bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define uint unsigned
#define pii pair<int,int>
#define pll pair<ll,ll>
#define IT iterator
#define PB push_back
#define fi first
#define se second
#define For(i,j,k) for (int i=(int)(j);i<=(int)(k);i++)
#define Rep(i,j,k) for (int i=(int)(j);i>=(int)(k);i--)
#define CLR(a,v) memset(a,v,sizeof(a));
#define CPY(a,b) memcpy(a,b,sizeof(a));
#define debug puts("wzpakking")
#define y1 ysghysgsygsh
using namespace std;
const int N=5005;
int n,mo,a[N];
int f[N][N];
int main(){
	scanf("%d%d",&n,&mo);
	int T=(n-1)/2;
	For(i,1,T+1) a[i]=1;
	For(i,n-T+1,n) a[i]=-1;
	Rep(i,n,1) a[i]+=a[i+1];
	For(i,2,n) a[i]*=-1;
	sort(a+2,a+n+1);
	reverse(a+2,a+n+1);
	For(i,2,n) a[i]++;
	f[0]=1;
	For(i,2,n) For(k,0,n-a[i])
		f[k+a[i]]=(f[k+a[i]]+f[k])%mo;
	int ans=0;
	For(i,0,n)
		ans=(ans+1ll*(n-i)*f[i][j])%mo;
	printf("%d\n",ans); 
}


Compiler output:
a.cc: In function 'int main()':
a.cc:31:13: error: incompatible types in assignment of 'int' to 'int [5005]'
   31 |         f[0]=1;
      |         ~~~~^~
a.cc:33:37: error: invalid operands of types 'int [5005]' and 'int [5005]' to binary 'operator+'
   33 |                 f[k+a[i]]=(f[k+a[i]]+f[k])%mo;
      |                            ~~~~~~~~~^~~~~
      |                                    |    |
      |                                    |    int [5005]
      |                                    int [5005]
a.cc:36:41: error: 'j' was not declared in this scope
   36 |                 ans=(ans+1ll*(n-i)*f[i][j])%mo;
      |                                         ^
Language: C++

#include<bits/stdc++.h>
#define ll long long
#define ld long double
#define db double
#define pint pair<int,int>
#define mk(x,y) make_pair(x,y)
#define fir first
#define sec second
#define Rep(x,y,z) for(int x=y;x<=z;x++)
#define Red(x,y,z) for(int x=y;x>=z;x--)
using namespace std;
const int MAXN=5e4+5,MAXM=1e5+5;
char buf[1<<12],*pp1=buf,*pp2=buf,nc;int ny;
inline char gc() {return pp1==pp2&&(pp2=(pp1=buf)+fread(buf,1,1<<12,stdin),pp1==pp2)?EOF:*pp1++;}
//inline char gc(){return getchar();}
inline int read(){
	int x=0;for(ny=1;nc=gc(),(nc<48||nc>57)&&nc!=EOF;)if(nc==45)ny=-1;if(nc<0)return nc;
	for(x=nc-48;nc=gc(),47<nc&&nc<58&&nc!=EOF;x=(x<<3)+(x<<1)+(nc^48));return x*ny;
}
int n,m,T;pint a[MAXM];
namespace Task1{
	bitset<MAXN>F[MAXN],tmp;int vis[MAXN],ans[MAXM];
	inline void Solve(){
		Rep(i,1,n)F[i].filp(i);
		Red(i,m,1){int x=a[i].fir,y=a[i].sec;F[x]=F[y]=F[x]|F[y];}
		tmp.set();Rep(i,1,n)tmp&=F[i];if(!tmp.any()){puts("-1");return;}
		int t=tmp._Find_first();vis[t]=1;
		Red(i,m,1){
			int x=a[i].fir,y=a[i].sec;
			if(vis[x]&&!vis[y])vis[y]=1,ans[i]=1;else if(vis[y]&&!vis[x])vis[x]=1,ans[i]=0;
		}Rep(i,1,m)putchar(ans[i]?'v':'^');puts("");
	}
}
namespace Task2{
	inline void Solve(){
		
	}
}
int main(){
//	freopen("std.in","r",stdin);
//	freopen("std.out","w",stdout);
	n=read(),m=read(),T=read();
	Rep(i,1,m)a[i]=(pint){read(),read()};
	if(T==1)Task1::Solve();else Task2::Solve();
	return 0;
}




Compiler output:
a.cc: In function 'void Task1::Solve()':
a.cc:24:32: error: 'class std::bitset<50005>' has no member named 'filp'; did you mean 'flip'?
   24 |                 Rep(i,1,n)F[i].filp(i);
      |                                ^~~~
      |                                flip
Language: C++

#include<bits/stdc++.h>
using namespace std;
const int N=100000+10;
const int M=100000+10;
typedef long long ll;
int n,m,T;
int x[M],y[M],pr[M];
void pri(){
	for(int i=1;i<=m;i++)
		cout<<(pr[i]?'^':'v');
}

bitset<N> b[N],tmp;
int g[N];
namespace uni{
	void work(){
		for(int i=1;i<=n;i++)
			b[i][i]=1;
		for(int i=m;i>=1;i--){
			f=(b[x[i]]|b[y[i]]);
			b[x[i]]=b[y[i]]=f;
		}
		f.set();
		for(int i=1;i<=n;i++)
			f&=b[i];
		int ans=0;
		for(int i=1;i<=n;i++)
			if(f[i]){
				ans=i;
				break;
			}
		if(!ans)
			puts("-1");
		else{
			g[ans]=1;
			for(int i=m;i>=1;i--){
				if(g[x[i]])
					g[y[i]]=1,pr[i]=1;
				else if(g[y[i]])
					g[x[i]]=1;
			}
			pri();
		}
	}
}
namespace nuni{
	int b[N],cnt[N];
	void work(){
		if(n==2)
			puts("-1");
		else{
			for(int i=1;i<=n;i++)
				b[i]=i,cnt[i]=1;
			for(int i=m;i>=1;i--){
				if(cnt[b[y[i]]]>1)
					pr[i]=1,cnt[b[y[i]]]--,cnt[b[x[i]]]++,b[y[i]]=b[x[i]];
				else
					cnt[b[y[i]]]++,cnt[b[x[i]]]--,b[x[i]]=b[y[i]];
			}
			pri();
		}
	}
}
int main(){
	cin>>n>>m>>T;
	for(int i=1;i<=m;i++)
		cin>>x[i]>>y[i];
	if(T==1)
		uni::work();
	else
		nuni::work();
	return 0;
}

Compiler output:
a.cc: In function 'void uni::work()':
a.cc:20:25: error: 'f' was not declared in this scope
   20 |                         f=(b[x[i]]|b[y[i]]);
      |                         ^
a.cc:23:17: error: 'f' was not declared in this scope
   23 |                 f.set();
      |                 ^
Language: C++

#include<bits/stdc++.h>

using namespace std;

#define ll  long long
#define ld  double

#define sz(x)   (int)x.size()
#define all(x)  x.begin(),x.end()

#define pb  emplace_back
#define X   first
#define Y   second

const int   N   = 5e4;

typedef pair<int,int>   ii;
typedef bitset<N>       bs;

int main()  {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int n;  cin >> n;
    int m;  cin >> m;
    int T;  cin >> T;

    vector<ii>  E;

    for(int i = 0 ; i < m ; ++i)    {
        int x;  cin >> x;
        int y;  cin >> y;

        E.pb(x,y);
    }

    reverse(all(E));

    if (T == 1) {
        vector<bs>  f(n,0);
        bs  S;

        for(int i = 0 ; i < n ; ++i)    f[i][i] = S[i] = 1;
        for(int i = 0 ; i < m ; ++i)    {
            int x = E[i].X - 1;
            int y = E[i].Y - 1;

            f[x] = f[y] = (f[x] | f[y]);
        }

        for(int i = 0 ; i < n ; ++i)
            S &= f[i];

        int x = n;

        for(int i = 0 ; i < n ; ++i)
            if (S[i])   {
                x = i;
                break;
            }

        if (x < n)  {
            vector<int> t(n,0); t[x] = 1;

            string res = "";

            for(int i = 0 ; i < m ; ++i)    {
                int x = E[i].X - 1;
                int y = E[i].Y - 1;

                if (t[x])   res += '^', t[y] = 1;
                else        res += 'v', t[x] = t[y];
            }
            reverse(all(res));  cout << res << endl;
        }
        else    cout << "-1";
    }
    if (T == 2) {
        if (n < 3)  return  cout << "-1",0;

        vector<int> f(n);
        vector<int> c(n);

        iota(all(f),0);
        fill(all(c),1);

        string res = "";

        for(int i = 0 ; i < m ; ++i)    {
            int x = E[i].X - 1;
            int y = E[i].Y - 1;

            if (c[f[x]] > 1)
                c[f[x]]--,
                c[f[y]]++,
                f[x] = f[y],
                res += 'v';
            else
                c[f[y]]--,
                c[f[x]]++,
                f[y] = f[x],
                res += '^';
        }
        reverse(all(res)));  cout << res << endl;
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:104:26: error: expected ';' before ')' token
  104 |         reverse(all(res)));  cout << res << endl;
      |                          ^
      |                          ;
Language: C++

#include <bits/stdc++.h>
 
#include <unistd.h>
 
using namespace std;
 
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl;
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}
 
 
typedef long long ll;
#define int ll
 
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(25)<< fixed<<p<<endl;
int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
const ll MOD = 1000000007;
//const ll MOD = 998244353;
// #define mp make_pair
//#define endl '\n'

void solve2(int n, int m) {
  if (n == 2) {
    cout << -1 << endl;
    return 0;
  }
  vi x(m), y(m);
  rep (i, m) {
    cin >> x[i] >> y[i];
    x[i]--; y[i]--;
  }

  vi num(n), w(n);
  rep (i, n) {
    num[i] = 1;
    w[i] = i;
  }

  string s;
  rrep (i, m) {
    if (num[x[i]] >= 2) {
      num[x[i]]--;
      num[y[i]]++;
      s += 'v';
    }
    else if (num[y[i]] >= 2) {
      num[y[i]]--;
      num[x[i]]++;
      s += '^';
    }
    else {
      num[x[i]]--;
      num[y[i]]++;
      s += 'v';
    }
  }

  reverse(all(s));
  cout << s << endl;
}

signed main() {
  int n, m, t;
  cin >> n >> m >> t;
  assert(t == 2);

  solve2(n, m);
}


Compiler output:
a.cc: In function 'void solve2(ll, ll)':
a.cc:54:12: error: return-statement with a value, in function returning 'void' [-fpermissive]
   54 |     return 0;
      |            ^
Language: C

#define _USE_MATH_DEFINES
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <cstdio>
#include <complex>
#include <numeric>
#include <string.h>
#include <random>
#include <cmath>
#define rep(i,n) for (int i = 0; i < (int)n; i++)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pi;
typedef pair<pi, pi> pp;
typedef pair<ll, ll> pl;
double PI = 3.141592653589793238462643383279;
const double EPS = 1e-9;
const ll MOD = 1000000007;
//const ll MOD = 998244353
const int inf = 1 << 30;
const ll linf = 1LL << 60;

int N, M, T;
int x[100000], y[100000];
bool b[50000];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> N >> M >> T;
    rep(i,M) cin >> x[i] >> y[i];
    rep(i,M) { x[i]--; y[i]--; }
    if (T == 1) {
        string ans;
        rep(i,M) ans.push_back('^');
        rep(i,N) {
            memset(b, 0, sizeof(b));
            b[i] = true;
            for (int j = M-1; j >= 0; j--) {
                b[x[j]] |= b[y[j]];
                b[y[j]] |= b[x[j]];
            }
            int sum = 0;
            for (int j = N-1; j >= 0; j--) sum += b[j];
            if (sum == N) {
                memset(b, 0, sizeof(b));
                b[i] = true;
                for (int j = M-1; j >= 0; j--) {
                    b[x[j]] |= b[y[j]];
                    b[y[j]] |= b[x[j]];
                    if (b[x[j]] && !b[y[j]]) {
                        if (x[j] < y[j]) ans[j] = 'v';
                    }
                    if (b[y[j]] && !b[x[j]]) {
                        if (y[j] < x[j]) ans[j] = 'v';
                    }
                }
                cout << ans << endl;
                return 0;
            }
        }
        cout << -1 << endl;
    }
}

Compiler output:
main.c:2:10: fatal error: iostream: No such file or directory
    2 | #include <iostream>
      |          ^~~~~~~~~~
compilation terminated.
Language: C++

#include <bits/stdc++.h>
#define debug(x) cerr<<#x<<'='<<x<<endl
#define set0(x) memset(x,0,sizeof(x))
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pii;
template<typename T> void read(T &x){
	x = 0;char ch = getchar();ll f = 1;
	while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
	while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
bitset<50050> alv[50050];
int n,m,u[50050],v[50050],vis[50050];
char ans[50050];
void solve1(){
	for(int i=1;i<=n;i++){
		alv[i].reset();
		alv[i][i] = 1;
	}
	for(int i=1;i<=m;i++){
		read(u[i]);
		read(v[i]);
	}
	for(int i=m;i>=1;i--){
		alv[u[i]]|=alv[v[i]];
		alv[v[i]]|=alv[u[i]];
	}
	bitset<50050> cc;
	cc.set();
	for(int i=1;i<=n;i++){
		cc&=alv[i];
	}
	int cho = 0;
	for(int i=1;i<=n;i++) if(cc[i])cho = i;
	if(!cho){
		cout<<-1<<endl;
		return;
	}
	vis[cho] = 1;
	for(int i=m;i>=1;i--){
		ans[i] = vis[u[i]]?'^':'v';
		vis[u[i]]|=vis[v[i]];
		vis[v[i]]|=vis[u[i]];
	}
	cout<<(ans+1)<<endl;
}
int cp[50050],cnt[50050];
void solve2(){
	if(n<=2){
		cout<<-1<<endl;
		return;
	}
	for(int i=1;i<=n;i++){
		cp[i] = i;
		cnt[i] = 1;
	}
	for(int i=1;i<=m;i++){
		read(u[i]);
		read(v[i]);
	}
	for(int i=m;i>=1;i--){
		if(cnt[cp[u[i]]]>cnt[cp[v[i]]]){
			ans[i] = 'v';
			cnt[cp[u[i]]]--;
			cnt[cp[v[i]]]++;
			cp[u[i]] = cp[v[i]];
		}else{
			ans[i] = '^';
			cnt[cp[v[i]]]--;
			cnt[cp[u[i]]]++;
			cp[v[i]] = cp[u[i]];
		}
	}
	cout<<(ans+1)<<endl;
}
int n,m,t;
int main() {
	read(n);read(m);read(t);
	if(t == 1){
		n = n;
		m = m;
		solve1();
	}
	if(t == 2){
		n = n;
		m = m;
		solve2();
	}
	return 0;
}


Compiler output:
a.cc:76:5: error: redefinition of 'int n'
   76 | int n,m,t;
      |     ^
a.cc:13:5: note: 'int n' previously declared here
   13 | int n,m,u[50050],v[50050],vis[50050];
      |     ^
a.cc:76:7: error: redefinition of 'int m'
   76 | int n,m,t;
      |       ^
a.cc:13:7: note: 'int m' previously declared here
   13 | int n,m,u[50050],v[50050],vis[50050];
      |       ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
	ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	int n, m;
	cin >> n >> m;
	int T;
	cin >> T;
	vector<int> x(m);
	vector<int> y(m);
	for(int i = 0; i < m; i++){
		cin >> x[i] >> y[i];
		x[i]--; y[i]--;
	}
	if(T == 1){
		using B = bitset<50000>;
		vector<B> cur(n);
		for(int i = 0; i < n; i++){
			cur[i][i].flip();
		}
		for(int i = 0; i < m; i++){
			cur[x[i]] |= cur[y[i]];
			cur[y[i]] |= cur[x[i]];
		}
		for(int i = 0; i < n; i++){
			if(cur[i].count() == n){
				vector<int> where(n, 0);
				where[i] = 1;
				string st(m, '.');
				for(int j = m-1; j >= 0; j--){
					st[j] = "^v"([where[x[i]] < where[y[i]]]);
					where[x[i]] |= where[y[i]];
					where[y[i]] |= where[x[i]];
				}
				cout << st << '\n';
				return 0;
			}
		}
		cout << -1 << '\n';
	} else {
		if(n == 2){
			cout << -1 << '\n';
			return 0;
		}
		for(int i = 0; i < m; i++){

		}
	}
}

Compiler output:
a.cc: In function 'int main()':
a.cc:32:60: error: expected ',' before '[' token
   32 |                                         st[j] = "^v"([where[x[i]] < where[y[i]]]);
      |                                                            ^
      |                                                            ,
a.cc:32:60: error: expected identifier before '[' token
a.cc: In lambda function:
a.cc:32:81: error: expected '{' before ')' token
   32 |                                         st[j] = "^v"([where[x[i]] < where[y[i]]]);
      |                                                                                 ^
a.cc: In function 'int main()':
a.cc:32:53: error: expression cannot be used as a function
   32 |                                         st[j] = "^v"([where[x[i]] < where[y[i]]]);
      |                                                 ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~