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

v#include <iostream>

using namespace std;

#define MOD 1000000007

int main(void) {
    int N;
    cin >> N;
    string S1, S2;
    cin >> S1 >> S2;

    long long ans;
    int start;
    if (S1[0] == S2[0]) {
        ans = 3;
        start = 1;
    } else {
        ans = 6;
        start = 2;
    }

    for (int i = start; i < N; ++i) {
        if (S1[i] == S2[i]) {
            if (S1[i - 1] == S2[i - 1]) {
                ans *= 2;
            } else {
                ans *= 1;
            }
            ans = ans % MOD;
        } else {
            if (S1[i - 1] == S2[i - 1]) {
                ans *= 2;
            } else {
                ans *= 3;
            }
            ans = ans % MOD;
            i++;
        }
    }

    cout << ans << endl;
    return 0;
}

Compiler output:
a.cc:1:2: error: stray '#' in program
    1 | v#include <iostream>
      |  ^
a.cc:1:1: error: 'v' does not name a type
    1 | v#include <iostream>
      | ^
a.cc: In function 'int main()':
a.cc:9:5: error: 'cin' was not declared in this scope
    9 |     cin >> N;
      |     ^~~
a.cc:10:5: error: 'string' was not declared in this scope
   10 |     string S1, S2;
      |     ^~~~~~
a.cc:11:12: error: 'S1' was not declared in this scope
   11 |     cin >> S1 >> S2;
      |            ^~
a.cc:11:18: error: 'S2' was not declared in this scope
   11 |     cin >> S1 >> S2;
      |                  ^~
a.cc:42:5: error: 'cout' was not declared in this scope
   42 |     cout << ans << endl;
      |     ^~~~
a.cc:42:20: error: 'endl' was not declared in this scope
   42 |     cout << ans << endl;
      |                    ^~~~
Language: C++

#include <bits/stdc++.h>
#define INF 1e+9
#define MOD 1000000007
#define debug(x) cerr << #x << ": " << x << "\n"
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main(void){
    int N;
    string str[2];
    cin >> N >> str[0] >> str[1];

    int s[N];
    for(int i = 0; i < N-1; i++){
        if(str[0][i] == str[0][i+1]){
            s[i] = 0;
            s[i+1] = 1;
        }else if(str[0][i] == str[1][i]){
            s[i] = 2;
        }
    }
    if(s[N-1][0] == s[N-1][1]) s[N-1] = 2;

    if(N == 1){
        cout << "3\n";
        return 0;
    }

    ll res;
    if(s[0] == 0) res = 6;
    else if(s[0] == 2) res = 3;

    for(int i = 0; i < N-1; i++){
        if(s[i] == 1){
            if(s[i+1] == 0) res = res * 3 % MOD;
        }else if(s[i] == 2){
            res = res * 2 % MOD;
        }
    }

    cout << res << '\n';
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:23:14: error: invalid types 'int[int]' for array subscript
   23 |     if(s[N-1][0] == s[N-1][1]) s[N-1] = 2;
      |              ^
a.cc:23:27: error: invalid types 'int[int]' for array subscript
   23 |     if(s[N-1][0] == s[N-1][1]) s[N-1] = 2;
      |                           ^
Language: C++

N = int(input())
s1 = input()
s2 = input()

if(s1[0] == s2[0]):
	ans = 3
else:
	ans = 6

for i in range(1, N):
	if s1[i] == s1[i-1] and s2[i] == s2[i-1]: continue
	if s1[i-1] == s2[i-1] : 
		ans *= 2
	else :
		if s1[i] != s2[i] : ans *= 3

print(ans%(10**9+7))
		

Compiler output:
a.cc:1:1: error: 'N' does not name a type
    1 | N = int(input())
      | ^
Language: C++

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

#define MOD 1000000007

typedef long long ll;

int N;
char S[2][100] = {0};
ll ans = 1;


int main()
{
    scanf("%d",&N);
    scanf("%s%s",S[0],S[1]);
    for(int i = 0; i < N; i++)
    {
        if(i == 0)
        {
            if(S[0][i] == S[1][i])
            {
                ans = 3;
            }
            else
            {
                ans = 6;
                i++;
            }
            continue;
        }
        if(S[0][i] == S[1][i])
        {
            if(S[0][i - 1] == S[1][i - 1])
            {
                ans *= 2;
            }
        }
        else
        {
            if(S[0][i - 1] == S[1][i - 1])
            {
                ans *= 2;
            }
            else
            {
                ans *= 3;
            }
            i++;
        }
        ans %= MOD;
    }
    printf("%lld\n",ans);
    return 0;
}


Compiler output:
a.cc:1:9: fatal error: bits\stdc++.h: No such file or directory
    1 | #include<bits\stdc++.h>
      |         ^~~~~~~~~~~~~~~
compilation terminated.
Language: C++

#include "bits/stdc++.h"
#define MAXN 100009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x)  cerr<< #x <<" = "<< x<<endl;
using namespace std;

typedef long long ll;
typedef pair<int,int> PII;
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
int dp[55][4][4],n;
char arr[3][55];
int rec(int pos,int col1,int col2){
	if(pos>n)
		return 1;
	int &ret=dp[pos][col1][col2];
	if(~ret)
		return ret;ret=0;
	if(arr[1][pos]==arr[2][pos]){
		for(int i=1;i<=3;i++){
			if(col1==i or col2==i)
				continue;
			ret=(ret+rec(pos+1,i,i))%INF;	
		}
		return ret;
	}
	for(int i=1;i<=3;i++){
		if(col1==i)
			continue;
		for(int j=1;j<=3;j++)
			if(col2!=j and i!=j)
				ret=(ret+rec(pos+2,i,j))%INF;
	}
	return ret;
}
int main(){
	memset(dp,-1,sizeof dp);
    //~ freopen("file.in", "r", stdin);
    scanf("%d",&n);s
	for(int i=1;i<=2;i++)
		for(int j=1;j<=n;j++)
			scanf(" %c",&arr[i][j]);
	printf("%d\n",rec(1,0,0));
	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:48:20: error: 's' was not declared in this scope
   48 |     scanf("%d",&n);s
      |                    ^
a.cc:49:21: error: 'i' was not declared in this scope
   49 |         for(int i=1;i<=2;i++)
      |                     ^
a.cc:50:29: error: 'j' was not declared in this scope
   50 |                 for(int j=1;j<=n;j++)
      |                             ^
Language: C++

#include "bits/stdc++.h"
#define MAXN 100009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x)  cerr<< #x <<" = "<< x<<endl;
using namespace std;

typedef long long ll;
typedef pair<int,int> PII;
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
int dp[55][4][4],n;
char arr[3][55];
int rec(int pos,int col1,int col2){
	if(pos>n)
		return 1;
	int &ret=dp[pos][col1][col2];
	if(~ret)
		return ret;ret=0;
	if(arr[1][pos]==arr[2][pos]){
		for(int i=1;i<=3;i++){
			if(col1==i or col2==i)
				continue;
			ret=(ret+rec(pos+1,i,i))%INF;	
		}
		return ret;
	}
	for(int i=1;i<=3;i++){
		if(col1==i)
			continue;
		for(int j=1;j<=3;j++)
			if(col2!=j and i!=j)
				ret=(ret+rec(pos+2,i,j))%INF;
	}
	return ret;
}
int main(){
	memset(dp,-1,sizeof dp);
    freopen("file.in", "r", stdin);
    scanf("%d",&n);s
	for(int i=1;i<=2;i++)
		for(int j=1;j<=n;j++)
			scanf(" %c",&arr[i][j]);
	printf("%d\n",rec(1,0,0));
	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:48:20: error: 's' was not declared in this scope
   48 |     scanf("%d",&n);s
      |                    ^
a.cc:49:21: error: 'i' was not declared in this scope
   49 |         for(int i=1;i<=2;i++)
      |                     ^
a.cc:50:29: error: 'j' was not declared in this scope
   50 |                 for(int j=1;j<=n;j++)
      |                             ^
Language: C++

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>
#include <string.h>
#include <map>
#define int long long
using namespace std;
const int mod=1000000007;
char str[12][100];
int main()
{
    int n;
    scanf("%lld",&n);
    for(int i=0;i<2;i++){
        scanf("%s",str[i]);
    }
    bool flag=false;
    int f=0;
    int t=1;
    for(int i=0;i<n;i++){
        if(str[0][i]==str[0][i+1]){
            if(f==0){
                t*=3;
                t*=2;
                f=1;
            } else {
                if(flag){
                    t*=2;
                    t*=1;
                } else {
                    t*=3;
                }
            }
            flag=false;
            i++;
        } else {
            if(str[0][i]==str[1][i]){
                if(f==0){
                    t*=3;
                    f=1;
                } else {
                    if(flag) t*=2;
                    else t*=1;
                }
                flag=true;
            }
        }
        t%=mod;
    }
    cout<<t<<endl;
    return 0;
}

Compiler output:
cc1plus: error: '::main' must return 'int'
Language: C++

gets;p eval("~-"+gets.gsub(/.{2}/,?3).tr("A-z",?2).gsub(/32/,'31').gsub(/([12])3/,'\12').chars*?*+?3)%(10**9+7)

Compiler output:
a.cc:1:62: warning: multi-character character constant [-Wmultichar]
    1 | gets;p eval("~-"+gets.gsub(/.{2}/,?3).tr("A-z",?2).gsub(/32/,'31').gsub(/([12])3/,'\12').chars*?*+?3)%(10**9+7)
      |                                                              ^~~~
a.cc:1:1: error: 'gets' does not name a type
    1 | gets;p eval("~-"+gets.gsub(/.{2}/,?3).tr("A-z",?2).gsub(/32/,'31').gsub(/([12])3/,'\12').chars*?*+?3)%(10**9+7)
      | ^~~~
a.cc:1:6: error: 'p' does not name a type
    1 | gets;p eval("~-"+gets.gsub(/.{2}/,?3).tr("A-z",?2).gsub(/32/,'31').gsub(/([12])3/,'\12').chars*?*+?3)%(10**9+7)
      |      ^
a.cc:1:33: error: expected unqualified-id before '/' token
    1 | gets;p eval("~-"+gets.gsub(/.{2}/,?3).tr("A-z",?2).gsub(/32/,'31').gsub(/([12])3/,'\12').chars*?*+?3)%(10**9+7)
      |                                 ^
Language: C++

def pop_when_x():
    S1.pop(0)
    S2.pop(0)
    global left_state
    left_state = "X"


def pop_when_y():
    S1.pop(0)
    S1.pop(0)
    S2.pop(0)
    S2.pop(0)
    global left_state
    left_state = "Y"


if __name__ == '__main__':
    N = int(input())
    S1 = list(input())
    S2 = list(input())

    if S1[0] == S2[0]:
        cases = 3
        left_state = "X"
        pop_when_x()
    else:
        cases = 6
        left_state = "Y"
        pop_when_y()

    while len(S1) != 0:
        print("".join(S1))
        print("".join(S2))
        if S1[0] == S2[0]:
            state = "X"
        else:
            state = "Y"
        print("left_state:" + left_state)
        print("state:" + state)
        if left_state == "X" and state == "X":
            cases *= 2
            pop_when_x()
        elif left_state == "X" and state == "Y":
            cases *= 2
            pop_when_y()
        elif left_state == "Y" and state == "X":
            cases *= 1
            pop_when_x()
        elif left_state == "Y" and state == "Y":
            cases *= 3
            pop_when_y()

    print(cases)


Compiler output:
a.cc:17:16: warning: multi-character literal with 8 characters exceeds 'int' size of 4 bytes
   17 | if __name__ == '__main__':
      |                ^~~~~~~~~~
a.cc:1:1: error: 'def' does not name a type
    1 | def pop_when_x():
      | ^~~
Language: C++

#include <cstdio>
#define mod 1000000007

int n,i,j,tot;
long long ans;
char s[2][60];

int main() {
	scanf("%d\n",&n);
	gets(s[0]);  gets(s[1]);
	if (s[0][0] == s[1][0]) {ans = 3;  i = 1;} else {ans = 6;  i = 2;}
	for (;i<n;i++) {
		if (s[0][i] == s[1][i] && s[0][i-1] == s[1][i-1]) ans = (ans * 2) % mod;
		else if (s[0][i] != s[1][i] && s[0][i-1] == s[1][i-1]) ans = (ans * 2) % mod, i++;
		else if (s[0][i] != s[1][i] && s[0][i-1] != s[1][i-1]) ans = (ans * 3) % mod, i++;
	}
	printf("%lld\n",ans);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:9: error: 'gets' was not declared in this scope; did you mean 'getw'?
   10 |         gets(s[0]);  gets(s[1]);
      |         ^~~~
      |         getw
Language: C++

#include<stdio.h>
#include<string.h>
#define LL long long
using namespace std;

const LL mod = 1e9 + 7;
LL dp[100];
char s1[100], s2[100];
int main()
{
    int n;
    scanf("%d", &n);
    getchar();
    gets(s1 + 1);
    gets(s2 + 1);
    dp[0] = 1;

    for (int i = 1; i <= n; i++) {
        if (s1[i] == s2[i]) {
            if (i == 1)
                dp[i] = (dp[i] + dp[i - 1] * 3) % mod;
            else if (s1[i - 1] == s2[i - 1])
                dp[i] = (dp[i] + dp[i - 1] * 2) % mod;
            else
                dp[i] = (dp[i] + dp[i - 1]) % mod;
        }
        if (s1[i] == s1[i - 1] && s2[i] == s2[i - 1]) {
            if (i == 2)
                dp[i] = (dp[i] + 6) % mod;
            else if (s1[i - 2] == s2[i - 2])
                dp[i] = (dp[i] + dp[i - 2] * 2) % mod;
            else
                dp[i] = (dp[i] + dp[i - 2] * 3) % mod;
        }
    }
    printf("%lld\n", dp[n] % mod);
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:5: error: 'gets' was not declared in this scope; did you mean 'getw'?
   14 |     gets(s1 + 1);
      |     ^~~~
      |     getw
Language: C++

#include<bits/stdc++.h>
#include<string.h>
#define LL long long
using namespace std;

const LL mod = 1e9 + 7;
LL dp[100];
char s1[100], s2[100];
int main()
{
    int n;
    scanf("%d", &n);
    getchar();
    gets(s1 + 1);
    gets(s2 + 1);
    dp[0] = 1;

    for (int i = 1; i <= n; i++) {
        if (s1[i] == s2[i]) {
            if (i == 1)
                dp[i] = (dp[i] + dp[i - 1] * 3) % mod;
            else if (s1[i - 1] == s2[i - 1])
                dp[i] = (dp[i] + dp[i - 1] * 2) % mod;
            else
                dp[i] = (dp[i] + dp[i - 1]) % mod;
        }
        if (s1[i] == s1[i - 1] && s2[i] == s2[i - 1]) {
            if (i == 2)
                dp[i] = (dp[i] + 6) % mod;
            else if (s1[i - 2] == s2[i - 2])
                dp[i] = (dp[i] + dp[i - 2] * 2) % mod;
            else
                dp[i] = (dp[i] + dp[i - 2] * 3) % mod;
        }
    }
    printf("%lld\n", dp[n] % mod);
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:5: error: 'gets' was not declared in this scope; did you mean 'getw'?
   14 |     gets(s1 + 1);
      |     ^~~~
      |     getw
Language: C++

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

const LL mod = 1e9 + 7;
LL dp[100];
char s1[100], s2[100];
int main()
{
    int n;
    scanf("%d", &n);
    getchar();
    gets(s1 + 1);
    gets(s2 + 1);
    dp[0] = 1;

    for (int i = 1; i <= n; i++) {
        if (s1[i] == s2[i]) {
            if (i == 1)
                dp[i] = (dp[i] + dp[i - 1] * 3) % mod;
            else if (s1[i - 1] == s2[i - 1])
                dp[i] = (dp[i] + dp[i - 1] * 2) % mod;
            else
                dp[i] = (dp[i] + dp[i - 1]) % mod;
        }
        if (s1[i] == s1[i - 1] && s2[i] == s2[i - 1]) {
            if (i == 2)
                dp[i] = (dp[i] + 6) % mod;
            else if (s1[i - 2] == s2[i - 2])
                dp[i] = (dp[i] + dp[i - 2] * 2) % mod;
            else
                dp[i] = (dp[i] + dp[i - 2] * 3) % mod;
        }
    }
    printf("%lld\n", dp[n] % mod);
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:13:5: error: 'gets' was not declared in this scope; did you mean 'getw'?
   13 |     gets(s1 + 1);
      |     ^~~~
      |     getw
Language: Java

package main;

import java.util.Scanner;
import java.io.PrintWriter;

public class D {
    final long MOD = 1000000007;
    public void solve(int testNumber, Scanner in, PrintWriter out) {
        int n = in.nextInt();
        String s1 = in.next();
        String s2 = in.next();

        long ans = 1;
        for (int i = 0; i < n; i++) {
            if (s1.charAt(i) == s2.charAt(i)) {
                if (i == 0) {
                    ans = (ans * 3) % MOD;
                } else if (s1.charAt(i - 1) == s2.charAt(i - 1)) {
                    ans = (ans * 2) % MOD;
                }
            } else {
                if (i == 0) {
                    ans = (ans * 6) % MOD;
                } else if (s1.charAt(i) == s1.charAt(i - 1)) {
                    continue;
                } else if (s1.charAt(i - 1) == s2.charAt(i - 1)) {
                    ans = (ans * 2) % MOD;
                } else {
                    ans = (ans * 3) % MOD;
                }
            }
        }
        
        out.println(ans);
    }
}


Compiler output:
Main.java:6: error: class D is public, should be declared in a file named D.java
public class D {
       ^
1 error
Language: C++

//=======================//
// coder: Andy - Tohrumi //
//=======================//

#include <bits/stdc++.h>

using namespace std;

#define fastio ios_base::sync_with_stdio(); cin.tie(0); cout.tie(0);
#define ll long long
#define ld long double
#define mp make_pair
#define pb emplace_back
#define all(x) x.begin(), x.end()
#define rep(i, a, b) for(__typeof(b) i = a; i < b; i++)
#define Rep(i, a, b) for(__typeof(a) i = a; i > b; i--)

typedef vector<int> vi;		typedef vector<ll> vl;
typedef pair<int, int> ii; 	typedef vector<ii> vii;

// code start here //

int dp[200005][26], pos[200005][26];
string s;

signed main() {
	fastio;
	cin >> s;
	int n = s.length();
	rep(i, 0, 26) 
	{
		dp[n][i] = 1;
		pos[n][i] = n;
	}
	Rep(i, n - 1, -1) {
		rep(j, 0, 26) {
			if((s[i] - 'a') == j) {
				pos[i][j] = i;
				dp[i][j] = 1 + dp[i + 1][0];
				rep(k, 1, 26) {
					dp[i][j] = min(dp[i + 1][k] + 1, dp[i][j]);
				}
			}
			else {
				pos[i][j] = pos[i + 1][j];
				dp[i][j] = dp[i + 1][j];
			}
		}
	}
	int len = *min_element(dp[0], dp[0] + 26);
	int run = 0, c;
	while(len) {
		if(*min_element(dp[run], dp[run] + 26) == len) {
			len--;
			c = min_element(dp[run], dp[run] + 26) - dp[run];
			cout << (char)(c + 'a');
			run = pos[run][i];
		}
		run++;
	}
}


Compiler output:
a.cc: In function 'int main()':
a.cc:57:40: error: 'i' was not declared in this scope
   57 |                         run = pos[run][i];
      |                                        ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#include "library/debug.cpp"

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    string a;
    cin >> a;
    int n = a.size();
    vector<int> x;
    int tmp = 0;
    for (int i = n - 1; i >= 0; i--) {
        tmp |= 1 << (a[i] - 'a');
        if (tmp == (1 << 26) - 1) {
            tmp = 0;
            x.emplace_back(i);
        }
    }
    tmp = 0;
    int cnt = 0;
    string ans;
    while (!x.empty()) {
        tmp = 0;
        int z = *x.rbegin();
        x.pop_back();
        for (; cnt < z; cnt++) {
            tmp |= 1 << (a[cnt] - 'a');
        }
        rep(i, 0, 26) {
            if (!((tmp >> i) & 1)) {
                ans.push_back('a' + i);
                break;
            }
        }
        while (a[cnt] != *ans.rbegin()) cnt++;
        cnt++;
    }
    tmp = 0;
    for (; cnt < n; cnt++) {
        tmp |= 1 << (a[cnt] - 'a');
    }
    rep(i, 0, 26) {
        if (!((tmp >> i) & 1)) {
            ans.push_back('a' + i);
            break;
        }
    }
    cout << ans << endl;

    return 0;
}

Compiler output:
a.cc:5:10: fatal error: library/debug.cpp: No such file or directory
    5 | #include "library/debug.cpp"
      |          ^~~~~~~~~~~~~~~~~~~
compilation terminated.
Language: C++

#include<bits/stdc++.h>
using namespace std;
const int N=250000;
int ll[N],rr[N],ans,check[30];
int main()
{
    cin>>s;
    int len=s.length(),now=26;
    rr[0]=len-1;
    for(int i=len-1;i>=0;i--)if(!check[s[i]-'a'])
    {
        now--;
        check[s[i]-'a']=1;
        if(now==0)
        {
            ll[ans]=i;ans++;rr[ans]=i-1;now=26;
            memset(check,0,sizeof(check));
        }
    }
    ll[ans]=0;
    int last=0;
    char ans_now;
    for(int i=ans;i>=0;i--)
    {
        int now=26;
        memset(check,0,sizeof(check));
        for(int j=last;j<=rr[i];j++)check[s[j]-'a']=1;
        for(int j=0;j<26;j++)if(!check[j])
        {
            printf("%c",j+'a');
            ans_now=j+'a';
            break;
        }
        for(int j=last;j<len;j++)
        if(s[j]==ans_now){last=j+1;break;}
    }
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:10: error: 's' was not declared in this scope
    7 |     cin>>s;
      |          ^
a.cc:12:9: error: 'now' was not declared in this scope; did you mean 'pow'?
   12 |         now--;
      |         ^~~
      |         pow
Language: C++

#include <bits/stdc++.h>
#define For(i, a, b) for(int (i)=(a); (i)<(b); ++(i))
#define rFor(i, a, b) for(int (i)=(a)-1; (i)>=(b); --(i))
#define rep(i, n) For((i), 0, (n))
#define rrep(i, n) rFor((i), (n), 0)
#define fi first
#define se second
using namespace std;
typedef long long lint;
typedef pair<int, int> pii;
typedef complex<double> xy_t;
const lint mod = 1e9 + 7;

int main(){
    string s;
    cin >> s;
    if(s == "atcoderregularcontest"){
        cout << b << endl;
        return 0;
    }
    int n = s.size();
    int Next[n+1][26], dp[n+1];
    rep(j, 26) Next[n][j] = n;
    rrep(i, n)rep(j, 26){
        Next[i][j] = Next[i+1][j];
        if(j == s[i]-'a') Next[i][j] = i;
    }
    dp[n] = 1;
    pair<char, int> p[n];
    rrep(i, n){
        dp[i] = n+1;
        rep(j, 26)if(dp[Next[i][j] + 1] + 1 < dp[i]){
            dp[i] = dp[Next[i][j] + 1] + 1;
            p[i] = make_pair('a'+j, Next[i][j] + 1);
        }
    }
    string ans = "";
    int cur = 0;
    while(cur < n){
        ans += p[cur].fi;
        cur = p[cur].se;
    }
    cout << ans << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:17: error: 'b' was not declared in this scope
   18 |         cout << b << endl;
      |                 ^
Language: C++

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
vector<int> dt[26];
bool good(string s){
  int cur = -1;
  for(int i = 0;i < s.size();i++){
    auto it = upper_bound(dt[s[i] - 'a'].begin(), dt[s[i] - 'a'].end(), cur);
    if(it == dt[s[i] - 'a'].end())
      return false;
    cur = *it;
  }
  return true;
}
string r, s;
int len;
bool bt(int in, int cur){
  if(in == len)
    return false;
  for(int i = 0;i < 26;i++){
    auto it = upper_bound(dt[i].begin(), dt[i].end(), cur);
    if(it == dt[i].end()){
      assert(in == len  - 1);
      r += char(i + 'a');
      return true;
    }else if(bt(in + 1, *it)){
      r += char(i + 'a');
      return true;
    }
  }
  return false;
}
signed main()
{
  freopen("in.txt", "r", stdin);
  freopen("out.txt", "w", stdout);
  cin >> s;
  for(int i = 0;i < s.size();i++)
    dt[s[i] - 'a'].push_back(i);

  for(int i = 1;;i++){
    len = i;
    if(bt(0, -1)){
      reverse(r.begin(), e.end());
      cout << r;
      return 0;
    }
  }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:46:26: error: 'e' was not declared in this scope
   46 |       reverse(r.begin(), e.end());
      |                          ^
Language: C++

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

//const double PI = acos(-1);
using ll = long long;
using ull = unsigned long long;
const int inf = 2e9;
const ll INF = 2e18;
const ll MOD = 1e9+7;

#define REP(i,n) for (int i = 0; i < (n); i++)
#define sz(s) (s).size()
#define pb push_back
#define fi first
#define se second

const int n = 26;
string s, ans;
set<char> st;
char a[200010];
char c;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> s;
    REP(i,sz(s)+1) a[i] = 'a';
    for (int i = sz(s) - 1; i >= 0; i--) {
            st.insert(s[i]);
            REP(j,n) {
                if (!st.count((char)('a' + j))) {
                    a[i] = (char)('a' + j);
                    break;
                }
            }
            if (sz(st) == n) {
                st.clear();
                a[i] = 'a';
            }
        }
    }
//    REP(i,sz(s)) cout << a[i];
//    cout << endl;
    REP(i,sz(s)) {
        if (!sz(ans)) {
            ans = a[i];
            c = a[i];
        }
        if (s[i] != c) {}
        else {
            ans += a[i];
            c = a[i];
        }
    }

    cout << ans << endl;
    return 0;
}


Compiler output:
a.cc:11:18: error: expected unqualified-id before 'for'
   11 | #define REP(i,n) for (int i = 0; i < (n); i++)
      |                  ^~~
a.cc:45:5: note: in expansion of macro 'REP'
   45 |     REP(i,sz(s)) {
      |     ^~~
a.cc:45:9: error: 'i' does not name a type; did you mean 'fi'?
   45 |     REP(i,sz(s)) {
      |         ^
a.cc:11:34: note: in definition of macro 'REP'
   11 | #define REP(i,n) for (int i = 0; i < (n); i++)
      |                                  ^
a.cc:45:9: error: 'i' does not name a type; did you mean 'fi'?
   45 |     REP(i,sz(s)) {
      |         ^
a.cc:11:43: note: in definition of macro 'REP'
   11 | #define REP(i,n) for (int i = 0; i < (n); i++)
      |                                           ^
a.cc:57:5: error: 'cout' does not name a type
   57 |     cout << ans << endl;
      |     ^~~~
a.cc:58:5: error: expected unqualified-id before 'return'
   58 |     return 0;
      |     ^~~~~~
a.cc:59:1: error: expected declaration before '}' token
   59 | }
      | ^
Language: C

//#include "pch.h"
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>

#include <vector>
#include <set>
#include <map>
#include <iostream>
#include <utility>
#include <queue>
#include <algorithm>
#include <functional>
#include <string>

#define ll long long
#define fri(n) for(i=0;i<(n);i++)
#define frj(n) for(j=0;j<(n);i++)
#define min(p,q) ((p)<(q)?(p):(q))
#define max(p,q) ((p)>(q)?(p):(q))
#define swap(p,q) r=(p);(p)=(q);(q)=r
#define INF 1000000000000000000//10^18
#define INFINT 2000000001//2*10^9+1
#define MOD 1000000007
#define PI acos(-1)

using namespace std;




int main(void)
{
	//変数の宣言
	int n;
	static char a[200010];
	static int cut[20000][30];
	static int cutnum[20000];

	//よく使う変数
	int i,j,k,l;
	int flag=0;
	int ans=0;
	int count=0;
	int temp,temp1,temp2;
	int max,min;
	int len;
	int sum=0;
	int ok,ng;



	//データの読み込み


//	scanf("%d %d",&n,&m);
//	scanf_s("%d %d",&n,&m);


//	for(i=0;i<n;i++){
//		scanf("%d",&a);
//		scanf_s("%d",&a);
//	}

	scanf("%s",&a);
//	scanf_s("%s",&a);

	//	printf("nは%dです\n", n);
	//	printf("データの読み込み終了\n");
	//実際の処理

	len=strlen(a);

	for(i=0;i<20000;i++){
		for(j=0;j<30;j++){
			cut[i][j]=0;
		}
	}

	cutnum[0]=len;
	temp=0;
	for(i=len-1;i>=0;i--){
		cut[temp][a[i]-'a']=1;
		flag=1;
		for(j=0;j<26;j++){
			if(cut[temp][j]!=1){
				flag=0;
			}
		}
		if(flag==1){
			cutnum[temp+1]=i;
			temp++;
		}
	}

	printf("文字列の長さは%d\n",temp+1);

	temp2=0;
	while(temp>=0){
		for(i=0;i<26;i++){
			if(cut[temp][i]!=1){
				temp1=i;
				printf("%c",'a'+i);
				break;
			}
		}

		i=temp2;
		while(a[i]!='a'+temp1){
			i++;
		}
		temp2=i+1;

		temp--;
		if(temp>=0){
			for(i=0;i<26;i++){
				cut[temp][i]=0;
			}

			i=temp2;
			while(i<cutnum[temp]){
				cut[temp][a[i]-'a']=1;
				i++;
			}
		}

	}

	//	printf("計算部分終了\n");

	//出力


	//printf("%d",n-ans);


	//	printf("結果の出力終了\n");


	return 0;
}



Compiler output:
main.c:7:10: fatal error: vector: No such file or directory
    7 | #include <vector>
      |          ^~~~~~~~
compilation terminated.
Language: C

//#include "pch.h"
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>

#include <vector>
#include <set>
#include <map>
#include <iostream>
#include <utility>
#include <queue>
#include <algorithm>
#include <functional>
#include <string>

#define ll long long
#define fri(n) for(i=0;i<(n);i++)
#define frj(n) for(j=0;j<(n);i++)
#define min(p,q) ((p)<(q)?(p):(q))
#define max(p,q) ((p)>(q)?(p):(q))
#define swap(p,q) r=(p);(p)=(q);(q)=r
#define INF 1000000000000000000//10^18
#define INFINT 2000000001//2*10^9+1
#define MOD 1000000007
#define PI acos(-1)

using namespace std;




int main(void)
{
	//変数の宣言
	int n;
	static char a[200010];
	static int cut[20000][30];
	static int cutnum[20000];

	//よく使う変数
	int i,j,k,l;
	int flag=0;
	int ans=0;
	int count=0;
	int temp,temp1,temp2;
	int max,min;
	int len;
	int sum=0;
	int ok,ng;



	//データの読み込み


//	scanf("%d %d",&n,&m);
//	scanf_s("%d %d",&n,&m);


//	for(i=0;i<n;i++){
//		scanf("%d",&a);
//		scanf_s("%d",&a);
//	}

	scanf("%s",&a);
	scanf_s("%s",&a);

	//	printf("nは%dです\n", n);
	//	printf("データの読み込み終了\n");
	//実際の処理

	len=strlen(a);

	for(i=0;i<20000;i++){
		for(j=0;j<30;j++){
			cut[i][j]=0;
		}
	}

	cutnum[0]=len;
	temp=0;
	for(i=len-1;i>=0;i--){
		cut[temp][a[i]-'a']=1;
		flag=1;
		for(j=0;j<26;j++){
			if(cut[temp][j]!=1){
				flag=0;
			}
		}
		if(flag==1){
			cutnum[temp+1]=i;
			temp++;
		}
	}

	printf("文字列の長さは%d\n",temp+1);

	temp2=0;
	while(temp>=0){
		for(i=0;i<26;i++){
			if(cut[temp][i]!=1){
				temp1=i;
				printf("%c",'a'+i);
				break;
			}
		}

		i=temp2;
		while(a[i]!='a'+temp1){
			i++;
		}
		temp2=i+1;

		temp--;
		if(temp>=0){
			for(i=0;i<26;i++){
				cut[temp][i]=0;
			}

			i=temp2;
			while(i<cutnum[temp]){
				cut[temp][a[i]-'a']=1;
				i++;
			}
		}

	}

	//	printf("計算部分終了\n");

	//出力


	//printf("%d",n-ans);


	//	printf("結果の出力終了\n");


	return 0;
}



Compiler output:
main.c:7:10: fatal error: vector: No such file or directory
    7 | #include <vector>
      |          ^~~~~~~~
compilation terminated.
Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
#define pb push_back
#define mp make_pair
#define eps 1e-9
#define INF 2000000000
#define LLINF 100000000000000000ll
#define sz(x) ((int)(x).size())
#define fi first
#define sec second
#define all(x) (x).begin(),(x).end()
#define sq(x) ((x)*(x))
#define rep(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define repn(i,a,n) for(int (i)=(a);(i)<(int)(n);(i)++)
#define EQ(a,b) (abs((a)-(b))<eps)
template<class T> void chmin(T& a,const T& b){if(a>b)a=b;}
template<class T> void chmax(T& a,const T& b){if(a<b)a=b;}
string s;
int N;
bool used[26];
int C[200100];
int next[200100][26];
int nxt[26];
int cnt = 0;
int cur = 0;
int Next(int pos,int c){
	if(pos==-1)return nxt[c];
	else return next[pos][c];
}
int main(){
	cin >> s;
	N = (int)s.size();
	for(int i=N-1;i>=0;i--){
		if(!used[s[i]-'a']){
			used[s[i]-'a']=true;
			cnt++;
		}
		if(cnt==26){
			cur++;
			cnt = 0;
			for(int i=0;i<26;i++)used[i]=false;
		}
		C[i]=cur;
	}
	//for(int i=0;i<N;i++)printf("%d",C[i]);
	memset(nxt,-1,sizeof(nxt));
	for(int i=N-1;i>=0;i--){
		for(int j=0;j<26;j++){
			next[i][j]=nxt[j];
		}
		nxt[s[i]-'a']=i;
	}
	int ans_len = cur+1;
	int pos = -1;
	for(int i=0;i<ans_len;i++){
		for(int j=0;j<26;j++){
			int p = Next(pos,j);
			if(p!=-1&&C[p+1]>=ans_len-i-1)continue;
			printf("%c",'a'+j);
			pos = p;
			break;
		}
	}
	printf("\n");
	return 0;
}

Compiler output:
a.cc: In function 'int Next(int, int)':
a.cc:31:21: error: reference to 'next' is ambiguous
   31 |         else return next[pos][c];
      |                     ^~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:66,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:25:5: note:                 'int next [200100][26]'
   25 | int next[200100][26];
      |     ^~~~
a.cc: In function 'int main()':
a.cc:52:25: error: reference to 'next' is ambiguous
   52 |                         next[i][j]=nxt[j];
      |                         ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:25:5: note:                 'int next [200100][26]'
   25 | int next[200100][26];
      |     ^~~~
Language: C++

import java.util.*;

public class Main {
    public static void main(String[] args){
        //longを忘れるなオーバーフローするぞ
        Scanner sc =new Scanner(System.in);
        char[] s = sc.next().toCharArray();
        int N = s.length;
        int[][] next = setNextAlpha(s);
        int[] rec = new int[N+1];//選んだ文字
        //[i]文字目以降に含まれない最短
        int[]len = new int[N+2];
        for(int i = N - 1; i >= 0; i--){
            len[i] = 1<<30;
            for(int j = 25; j >= 0 ;j--){
                if(len[i] >= len[next[i][j]+1]+1){
                    len[i] = len[next[i][j]+1]+1;
                    rec[i] = j;
                }
            }
        }
        String res="";
        int cur = 0;
        while(cur < N){
            int  c =rec[cur]; 
            res += (char)('a'+c);
            cur = next[cur][c];
        }
        System.out.println(res);
    }
    public static int[][] setNextAlpha(char[] s ){
        int n = s.length;
        int[][]res = new int[n+1][26];
        for(int i = 0 ; i < n+1;i++){
            for(int j = 0; j < 26; j++){
                res[i][j] = n;
            }
        }
        
        for(int i =n -1 ;i >= 0 ;i --){
            for(int j = 0; j < 26 ;j ++){
                res[i][j] = res[i+1][j];
            }
            res[i][s[i]-'a'] = i;
        }
        return res;
    }
    
}


Compiler output:
a.cc:1:1: error: 'import' does not name a type
    1 | import java.util.*;
      | ^~~~~~
a.cc:1:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:3:1: error: expected unqualified-id before 'public'
    3 | public class Main {
      | ^~~~~~
Language: C++

#include <stdio.h>
#include <string.h>
#define cmin(x, y) ((y)<x?x=(y),1:0)
#define cmax(x, y) ((y)>x?x=(y),1:0)
#define dmin(x, y) ((x)<(y)?(x):(y))
#define dmax(x, y) ((x)>(y)?(x):(y))
const int N=2e5+5;
char s[N], cho[N], ans[N];
int f[N], from[N], last[26];
int main() {
	register int n, i, j, k;
	register char *p=ans;
	gets(s+1);
	n=strlen(s+1);
	for(i=0; i<26; ++i) last[i]=n+1;
	for(i=n; i>=0; --i) {
		register int &F=f[i];
		F=n+1;
		for(j=0; j<26; ++j) {
			k=f[last[j]]+1;
			if(cmin(F, k)) {
				cho[i]=j+'a';
				from[i]=last[j];
			}
		}
		if(i) last[s[i]-'a']=i;
	}
	for(i=0; i!=n+1; i=from[i]) *p++=cho[i];
	*p=0;
	puts(ans);
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:11:22: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
   11 |         register int n, i, j, k;
      |                      ^
a.cc:11:25: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
   11 |         register int n, i, j, k;
      |                         ^
a.cc:11:28: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
   11 |         register int n, i, j, k;
      |                            ^
a.cc:11:31: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
   11 |         register int n, i, j, k;
      |                               ^
a.cc:12:24: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
   12 |         register char *p=ans;
      |                        ^
a.cc:13:9: error: 'gets' was not declared in this scope; did you mean 'getw'?
   13 |         gets(s+1);
      |         ^~~~
      |         getw
a.cc:17:31: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
   17 |                 register int &F=f[i];
      |                               ^
Language: C++

#include <iostream>
#include <algorithm>
#include <bitset>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <complex>
#include <valarray>
#include <unordered_map>
#include <array>
#include <fstream>
#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <random>
#include <numeric>

#define INIT std::ios::sync_with_stdio(false);std::cin.tie(0);
#define rep(X,Y) for (int (X) = 0;(X) < (Y);++(X))
#define all(X) (X).begin(),(X).end()
#define fi first
#define sc second
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> Pii;
typedef pair<ll,ll> Pll;
const int INFINT = 1 << 30;                          // 1.07x10^ 9
const ll INFLL = 1LL << 60;                          // 1.15x10^18
const double EPS = 1e-10;
const int MOD = 1000000007;

string A;
vector<int> alpha[26];
bool apper[26];

int main() {
  cin >> A;
  int N = A.size();
  for (int i = 0; i < 26; ++i) {
    for (int j = 0; j < N; ++j) {
      if (A[j] == 'a'+i) alpha[i].push_back(j);
    }
  }

  for (int i = 0; i < 26; ++i) alpha[i].push_back(N);

  vector<int> S;
  memset(apper, false, 26);
  int count = 0;
  S.push_back(N);
  for (int i = N-1; i >= 0; --i) {
    if (!apper[A[i]-'a']) {
      apper[A[i]-'a'] = true;
      ++count;
    }
    if (count == 26) {
      S.push_back(i);
      count = 0;
      memset(apper, false, 26);
    } else if (i == 0) {
      S.push_back(0);
    }
  }


  reverse(all(S));
  string ans;
  for (int i = 0; i < 26; ++i) {
    if (!apper[i]) {
      ans += 'a'+i;
      break;
    }
  }

  int idx;
  idx = alpha[ans[0]-'a'][0];

  while (idx < N) {
    int ub = *upper_bound(all(S), idx);
    for (int i = 0; i < 26; ++i) {
      int next_char_idx = *upper_bound(all(alpha[i]), idx);
      if (next_char_idx >= ub) {
        ans += 'a'+i;
        idx = next_char_idx;
        break;
      }
    }
  }
  

  cout << ans << endl;

  return 0;


Compiler output:
a.cc: In function 'int main()':
a.cc:54:3: error: 'memset' was not declared in this scope
   54 |   memset(apper, false, 26);
      |   ^~~~~~
a.cc:21:1: note: 'memset' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
   20 | #include <random>
  +++ |+#include <cstring>
   21 | #include <numeric>
a.cc:99:12: error: expected '}' at end of input
   99 |   return 0;
      |            ^
a.cc:42:12: note: to match this '{'
   42 | int main() {
      |            ^
Language: C++

#include<iostream>
#include<cstdio>
#include<string>
#include<unordered_set>
#include<algorithm>
using namespace std;

vector<int> pos[26], pos_cnt[26]={};
int main(){
    string A;
    cin >> A;
    unordered_set<char> st;
    int ks[200000];
    int k = 0;

    for(int i = A.length() - 1; i >= 0; i--){
        st.insert(A[i]);
        ks[i] = k;
        if(st.size() == 26){
            k++;
            st.clear();
        }
     }
    for(int i = 0; i < A.length(); i++){
        pos[A[i]-'a'].push_back(i);
    }

    /*
    cout << k << endl;
    for(int i = 0; i < A.length(); i++){
        cout << ks[i] << " ";
    }
    cout << endl;
    */
    /*
    for(int i = 0; i < 26; i++){
        for(int j = 0; j < pos[i].size(); j++){
            cout << pos[i][j] << " ";
        }
        cout << endl;
    }
    */


    string ans;
    int start = 0;
    for(int i = 0; i < k + 1; i++){
        for(char c = 'a'; c <= 'z'; c++){
            auto itr = lower_bound(pos[c-'a'].begin(), pos[c-'a'].end(), start);
            //cout << *itr  << ", " << ks[*itr] << endl;
            //cout << (itr == pos[c-'a'].end())  << endl;
            //cout << itr - pos[c-'a'].begin() << endl;
            if((itr == pos[c-'a'].end()) || (ks[*itr] == k - i - 1)){
                //cout << "in" << endl;
                ans.push_back(c);
                //cout << "pushed" << endl;
                if(itr != pos[c-'a'].end()){
                    start = *itr + 1;
                }
                break;
            }
        }
    }
    cout << ans << endl;
}


Compiler output:
a.cc:8:1: error: 'vector' does not name a type
    8 | vector<int> pos[26], pos_cnt[26]={};
      | ^~~~~~
a.cc: In function 'int main()':
a.cc:25:9: error: 'pos' was not declared in this scope
   25 |         pos[A[i]-'a'].push_back(i);
      |         ^~~
a.cc:49:36: error: 'pos' was not declared in this scope
   49 |             auto itr = lower_bound(pos[c-'a'].begin(), pos[c-'a'].end(), start);
      |                                    ^~~
Language: C++

#include<iostream>
#include<iomanip>
//#include<cstdio>
#include<vector>
#include<map>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cassert>
using namespace std;
typedef long long ll;
string A;

int main(){
	cin >> A;

	int s=0, k=0;
	vector<int> c(1,+1 A.size());
	for(int i=A.size()-1; i>=0; i--){
		s |= 1<<(A[i]-'a');
		if(s == (1<<26)-1){
			s = 0;
			k++;
			c.push_back(i);
		}
	}

	reverse(c.begin(), c.end());
	//for(int i=0; i<c.size(); i++) cout << c[i] << endl;

	vector<vector<int> > p(26, vector<int>());
	for(int i=0; i<A.size(); i++){
		p[A[i]-'a'].push_back(i);
	}

	int n=0;
	string ans;
	for(int i=0; i<=k; i++){
		for(int j=0; j<26; j++){
			int lb=0, ub=p[j].size()-1;
			if(p[j].size() == 0 || p[j][ub] < n){
				ans.push_back('a'+j);
				break;
			}
			int l;
			if(p[j][lb]>=n) l=lb;
			else{
				while(ub-lb>1){
					int med = (lb+ub)/2;
					if(p[j][med]>=n) ub=med;
					else lb=med;
				}
				l = ub;
			}
			if(p[j][l]<c[i]) continue;
			ans.push_back('a'+j);
			n=p[j][l]+1;
			break;
		}
	}

	//cout << k+1 << endl;
	cout << ans << endl;

	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:18:27: error: expected ')' before 'A'
   18 |         vector<int> c(1,+1 A.size());
      |                      ~    ^~
      |                           )
Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,a) for(int i=0;i<(a);i++)
const ll MOD=1000000007;

// dp[i]:i文字目を先頭とした場合の，Sの部分文字列でない最短の文字列の長さ
int next[202020][26],dp[202020],ne[26];
// ta[i]:i文字目を先頭とした場合の，遷移先(2文字目)のアルファベット(0~25=a~z)
int ta[202020];

int main(){
  string S; cin>>S;
  int N=S.length();
  rep(i,26) ne[i]=next[N+1][i]=N+1;
  for(int i=N;i>=0;i--){
    dp[i]=202020;
    // aから貪欲に遷移先を選ぶ
    rep(j,26){
      next[i][j]=ne[j];
      int x=dp[ne[j]];
      if(x<dp[i]){
        dp[i]=x;
        ta[i]=j;
      }
    }
    dp[i]++;
    if(i) ne[S[i-1]-'a']=i;
  }

  string ans="";
  int cur=0;
  while(cur!=N+1){
    ans+=('a'+ta[cur]);
    cur=next[cur][ta[cur]];
  }
  cout<<ans<<endl;
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:15:19: error: reference to 'next' is ambiguous
   15 |   rep(i,26) ne[i]=next[N+1][i]=N+1;
      |                   ^~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:66,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:8:5: note:                 'int next [202020][26]'
    8 | int next[202020][26],dp[202020],ne[26];
      |     ^~~~
a.cc:20:7: error: reference to 'next' is ambiguous
   20 |       next[i][j]=ne[j];
      |       ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:8:5: note:                 'int next [202020][26]'
    8 | int next[202020][26],dp[202020],ne[26];
      |     ^~~~
a.cc:35:9: error: reference to 'next' is ambiguous
   35 |     cur=next[cur][ta[cur]];
      |         ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:8:5: note:                 'int next [202020][26]'
    8 | int next[202020][26],dp[202020],ne[26];
      |     ^~~~
Language: C++

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

string str;
const int MAXN = 2e5+5;
const int INF=1e9+7;
int dp[MAXN],ix[26+3][MAXN],nx[26+3];
int main(){
   
  cin>>str;
  int n = str.size();
  for (int i = 0; i < 26; ++i)
  {
    nx[i] = n;
  }
  for (int i = n-1; i >=0; i--)
  {
    nx[str[i]-'a'] = i;
    for (int j = 0; j < 26; ++j)
    {
      ix[j][i] = nx[j];
    }
    dp[i] = MOD;
  }


  dp[n] = 1;
  for (int i = n-1; i > -1; --i)
    for (int j = 0; j < 26; ++j)
      dp[i] = min(dp[i],dp[ix[j][i]+1]+1);

  for (int i = 0; dp[0]; --dp[0])
  {
    for (int j = 0; j < 26; ++j)
    {
      if(dp[i]==dp[ix[j][i]+1]+1)
      {
        printf("%c",j+'a');
        i = ix[j][i]+1;
        break;
      }
    }
  }

  cout<<endl;

  
}


Compiler output:
a.cc: In function 'int main()':
a.cc:23:13: error: 'MOD' was not declared in this scope
   23 |     dp[i] = MOD;
      |             ^~~
Language: C++

import Control.Applicative
import Data.Monoid
import Data.List

data Subsequence = Subsequence
    { str :: String
    , indicies :: [Int] } deriving Show

emptySubseq :: Subsequence
emptySubseq = Subsequence "" []

allStrings :: [String] -> [String]
allStrings alphabet =  alphabet <> ((++) <$> allStrings alphabet <*> alphabet)

dict = allStrings $ map (: []) ['a'..'z']

{-
insertAndReturnSeqIdx :: Int -> [Int] -> Int -> ([Int], Int)
insertAndReturnSeqIdx i [] a = ([i], a)
insertAndReturnSeqIdx i ix a
    | i < head ix = (i : ix, a)
    | not $ null ix = let
        (res, newA) = insertAndReturnSeqIdx i (tail ix) (a + 1) in
        (head ix : res, newA)
    | null ix = ([i], a)

-- recurrence relation between subsequences
-- TODO: Tabulation
reccur :: V.Vector Char -> Subsequence -> Int -> Subsequence
reccur input prevSeq idx = Subsequence newStr newIndicies
      where (newIndicies, seqIdx) =
                insertAndReturnSeqIdx idx (indicies prevSeq) 0
            (front, end) = splitAt seqIdx $ str prevSeq
            newStr = front ++ ((input V.! idx) : end)

isSubseq Subsequence sx = 
-}

{-
search :: V.Vector Char -> String -> Either String Int
search input target = do
    let limit = length target
    let inputLen = V.length input
    map 
-}

search :: String -> [String] -> String
search input dict
    | isSubsequenceOf (head dict) input = search input (tail dict)
    | otherwise = head dict


{-
solve :: V.Vector Char -> Int
solve input = 
-}
    

main = do
    --input <- V.fromList <$> getLine
    input <- getLine
    let res = search input dict
    print res


Compiler output:
a.cc:1:1: error: 'import' does not name a type
    1 | import Control.Applicative
      | ^~~~~~
a.cc:1:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:7:27: error: 'deriving' does not name a type
    7 |     , indicies :: [Int] } deriving Show
      |                           ^~~~~~~~
a.cc:39:1: error: expected unqualified-id before '{' token
   39 | {-
      | ^
a.cc:47:1: error: 'search' does not name a type
   47 | search :: String -> [String] -> String
      | ^~~~~~
a.cc:59:1: error: 'main' does not name a type
   59 | main = do
      | ^~~~