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

#include <bits/stdc++.h>
#define REP(i,n) for (long i=0;i<(n);i++)
#define FOR(i,a,b) for (long i=(a);i<(b);i++)
#define RREP(i,n) for(long i=n;i>=0;i--)
#define RFOR(i,a,b) for(long i=(a);i>(b);i--)
#define dump1d_arr(array) REP(i,array.size()) cerr << #array << "[" << (i) << "] ==> " << (array[i]) << endl;
#define dump2d_arr(array) REP(i,array.size()) REP(j,array[i].size()) cerr << #array << "[" << (i) << "]" << "[" << (j) << "] ==> " << (array[i][j]) << endl;
#define dump(x)  cerr << #x << " => " << (x) << endl;
#define CLR(vec) { REP(i,vec.size()) vec[i] = 0; } 
#define llINF (long long) 9223372036854775807
#define loINF (long) 2147483647
#define shINF (short) 32767
#define SORT(c) sort((c).begin(),(c).end())
#define DEBUG

using namespace std;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef pair<int,int> pr;
typedef long long LL;
typedef vector<LL> Vll;

long N, K;
int t;
short c = 0;
short total = 0;
ll data[100000] = {0};
// memset( data , 0 , sizeof(data) );
Vll ans;

int main(){
    cin >> N;
    REP(i, N){
        cin >> data[i];
    }
    sort(data, data+N);
    for(int i= N-1; i >= 0; i--){
        // // cout << data[i];
        if (data[i] == 0) break;
        if(ans.size() >= 2){
            break;
        }
        if (data[i] == data[i - 1]){
            ans.push_back(data[i]);
            i--;
        }
    }
    if(ans.size() >= 2){
            cout << ans[0] * ans[1];
            return 0;
    }else{
        cout << 0;
        return 0;
    }
}

Compiler output:
a.cc:27:1: error: 'll' does not name a type; did you mean 'Vll'?
   27 | ll data[100000] = {0};
      | ^~
      | Vll
a.cc: In function 'int main()':
a.cc:34:20: error: invalid types '<unresolved overloaded function type>[long int]' for array subscript
   34 |         cin >> data[i];
      |                    ^
a.cc:36:20: error: invalid operands of types '<unresolved overloaded function type>' and 'long int' to binary 'operator+'
   36 |     sort(data, data+N);
      |                ~~~~^~
a.cc:39:17: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   39 |         if (data[i] == 0) break;
      |                 ^
a.cc:43:17: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   43 |         if (data[i] == data[i - 1]){
      |                 ^
a.cc:43:28: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   43 |         if (data[i] == data[i - 1]){
      |                            ^
a.cc:44:31: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   44 |             ans.push_back(data[i]);
      |                               ^
Language: C

#include<iostream>
#include<unordered_map>
#include <queue>

//ものすごく原始的な比較
struct myless {
	bool operator()(int x, int y) const {
		return x<y;
	}
};

typedef int MYINT;
typedef std::priority_queue<MYINT,std::vector<MYINT>,myless> P_Queue;
typedef std::unordered_map<MYINT,unsigned int> SET;


//////////////////////////////////
int main(void) {
	unsigned int N;
	P_Queue Q;

	std::cin >> N;

	//inputfase
	//binary insert
	for (int i = 0; i < N; i++) {
		MYINT temp;
		std::cin >> temp;
		Q.push(temp);
	}

	//完全にsort出来ない,闇
	
	SET set;
	MYINT max1, max2;

	int count = 0;
	while (!Q.empty()) {
		MYINT temp=Q.top();

		if (set.find(temp) != set.end()) {
			if (count == 0) {
				//max1,max1,...
				max1 = temp;
				set[temp]++;
			}

			if (count >= 1) {
				if (max1 != temp) {
					//max1,max1,max2,max2
					max2 = temp;
				}
				else {
					//max1,max1,max1,...
					set[temp]++;
				}
			}
			count++;
			if (set[max1] == 4) {
				//max1,max1,max1,max1
				max2 = max1;
				break;
			}
		}
		else set[temp] = 1;

		Q.pop();
	}

	std::cout << max1*max2 << std::endl;

	return 0;
}


Compiler output:
main.c:1:9: fatal error: iostream: No such file or directory
    1 | #include<iostream>
      |         ^~~~~~~~~~
compilation terminated.
Language: C++

#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <utility>
#include <iomanip>
#include <algorithm>
#include <functional>
using namespace std;

#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }


int N;
map<long long, int> ma;

int main() {
	while (cin >> N) {
		ma.clear();
		for (int i = 0; i < N; ++i) {
			long long a;
			cin >> a;
			ma[-a]++;
		}
		long long big[2] = { 0 };
		for (int i = 0; i < 2; ++i) big[i] = 0;
		int iter = 0;
		for (map<long long, int>::iterator it = ma.begin(); it != ma.end(); ++it) {
			while (it->second >= 2) {
				big[iter++] = it->first;
				it->second -= 2:
				if (iter >= 2) break;
			}
			if (iter >= 2) break;
		}
		cout << big[0] * big[1] << endl;
	}
}

















Compiler output:
a.cc: In function 'int main()':
a.cc:55:48: error: expected ';' before ':' token
   55 |                                 it->second -= 2:
      |                                                ^
      |                                                ;
Language: C++

#include<bits/stdc++.h>
using namespace std;
int n,mx1,mx2;
map<int,int> mp;
long long ans;
 int main()
{
	scanf("%d",&n);
	for (int i=1;i<=n;++i) 
	{
		int x;
		scanf("%d",&x);
		if (mp[x]==1)
		{
			if (x>mx1) mx2=mx1,mx1=x;
			else if (x>mx2) mx2=x;
			mp[x]=0;
		}
		else mp[x]=1;
	}
	ans=1LL*mx1*mx2;
	printf("%lld",ans);
}#include<bits/stdc++.h>
using namespace std;
int n,mx1,mx2;
map<int,int> mp;
long long ans;
 int main()
{
	scanf("%d",&n);
	for (int i=1;i<=n;++i) 
	{
		int x;
		scanf("%d",&x);
		if (mp[x]==1)
		{
			if (x>mx1) mx2=mx1,mx1=x;
			else if (x>mx2) mx2=x;
			mp[x]=0;
		}
		else mp[x]=1;
	}
	ans=1LL*mx1*mx2;
	printf("%lld",ans);
}

Compiler output:
a.cc:23:2: error: stray '#' in program
   23 | }#include<bits/stdc++.h>
      |  ^
a.cc:23:3: error: 'include' does not name a type
   23 | }#include<bits/stdc++.h>
      |   ^~~~~~~
a.cc:25:5: error: redefinition of 'int n'
   25 | int n,mx1,mx2;
      |     ^
a.cc:3:5: note: 'int n' previously declared here
    3 | int n,mx1,mx2;
      |     ^
a.cc:25:7: error: redefinition of 'int mx1'
   25 | int n,mx1,mx2;
      |       ^~~
a.cc:3:7: note: 'int mx1' previously declared here
    3 | int n,mx1,mx2;
      |       ^~~
a.cc:25:11: error: redefinition of 'int mx2'
   25 | int n,mx1,mx2;
      |           ^~~
a.cc:3:11: note: 'int mx2' previously declared here
    3 | int n,mx1,mx2;
      |           ^~~
a.cc:26:14: error: redefinition of 'std::map<int, int> mp'
   26 | map<int,int> mp;
      |              ^~
a.cc:4:14: note: 'std::map<int, int> mp' previously declared here
    4 | map<int,int> mp;
      |              ^~
a.cc:27:11: error: redefinition of 'long long int ans'
   27 | long long ans;
      |           ^~~
a.cc:5:11: note: 'long long int ans' previously declared here
    5 | long long ans;
      |           ^~~
a.cc:28:6: error: redefinition of 'int main()'
   28 |  int main()
      |      ^~~~
a.cc:6:6: note: 'int main()' previously defined here
    6 |  int main()
      |      ^~~~
Language: C++

#include <assert.h>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <numeric>
#include <functional>
#include <iostream>
#include <string>
#include <array>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <complex>
#include <bitset>
typedef long long ll;
typedef unsigned long long ull;

using namespace std;


template <typename T>
struct Counter {
  map<T, ll> cnt;
  void add(T key) {
    if (cnt.count(key)) {
      cnt[key]++;
    } else {
      cnt[key] = 1;
    }
  }
  ll get(T key) {
    if (cnt.count(key)) {
      return cnt[key];
    } else {
      return 0;
    }
  }
  typename map<T, ll>::iterator begin() {
    return cnt.begin();
  }
  typename map<T, ll>::iterator end() {
    return cnt.end();
  }
  typename map<T, ll>::reverse_iterator rbegin() {
    return cnt.rbegin();
  }
  typename map<T, ll>::reverse_iterator rend() {
    return cnt.rend();
  }
};


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

  int N;
  cin >> N;
  Counter<int> counter;

  for (int i = 0; i < N; i++) {
    int a;
    cin >> a;
    counter.add(a);
  }

  ll first = 0;
  ll second = 0;

  for (auto it = counter.rbegin(); it!= counter.rend(); it++) {
    if (i->second >= 2) {
      if (first == 0) {
        first = i->first;
        if (i->second >= 4) {
          second = i->first;
          break;
        }
      } else if (second == 0) {
        second = i->first;
        break;
      }
    }
  }

  cout << first * second << endl;
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:75:9: error: 'i' was not declared in this scope; did you mean 'it'?
   75 |     if (i->second >= 2) {
      |         ^
      |         it
Language: C++

#include <iostream>
#include <string>
#include <algorithm>
#include <math.h>
#include <set>
#include <string>
#include <vector>
#include <array>
#include <stdlib.h>

#define INT_MAX 2000000000
#define MOD 1000000007
#define ll long long;
#define REP(i,a,b) for(i = (a); i < (b); i++)
#define rep(i,n) REP(i,0,n)
#define bitget(a,b) (((a) >> (b)) & 1)

using namespace std;

int i, j, k;

int main() {
	int n;
	int a[100000];
	cin >> n;
	rep(i, n) {
		cin >> a[i];
	}
	sort(a,a+n);
	ll int d = 1;
	ll int ans1 = 0, ans2 = 0;
	for (i = n - 2; i > -1; i--) {
		if (a[i] == a[i + 1]) {
			d++;
		}
		else {
			d = 1;
		}
		if (d == 2) {
			if (ans1 == 0) {
				ans1 = a[i];
				d = 0;
			}
			else {
				ans2 = a[i];
				d = -1;
			}
		}
		if (d == -1) {
			break;
		}
	}
	cout << ans1*ans2 << endl;

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:17: error: declaration does not declare anything [-fpermissive]
   13 | #define ll long long;
      |                 ^~~~
a.cc:30:9: note: in expansion of macro 'll'
   30 |         ll int d = 1;
      |         ^~
a.cc:13:17: error: declaration does not declare anything [-fpermissive]
   13 | #define ll long long;
      |                 ^~~~
a.cc:31:9: note: in expansion of macro 'll'
   31 |         ll int ans1 = 0, ans2 = 0;
      |         ^~
Language: C

#include <stdio.h>
#include <stdlib.h>

int compar_int(int *a, int *b) {
	if (*a > *b) return 1;
	else if (*a == *b) retutn 0;
	return -1;
}

int main() {
	int ans;
	int l[2];
	l[0] = 0; l[1] = 0;
	int N;
	scanf("%d", &N);
	int A[N];
	for (int i = 0; i < N; i++) scanf("%d", A+i);
	
	qsort(A, N, sizeof(int), compar_int);

	for (int i = N-1; i > 0 && l[1] == 0; i--) {
		if (A[i] == A[i-1]) {
			if (!l[0]) l[0] = A[i];
			else l[1] = A[i];
			i--;
		}
	}

	ans = l[0] * l[1];

	printf("%d\n", ans);

	return 0;	
}


Compiler output:
main.c: In function 'compar_int':
main.c:6:28: error: 'retutn' undeclared (first use in this function)
    6 |         else if (*a == *b) retutn 0;
      |                            ^~~~~~
main.c:6:28: note: each undeclared identifier is reported only once for each function it appears in
main.c:6:34: error: expected ';' before numeric constant
    6 |         else if (*a == *b) retutn 0;
      |                                  ^~
      |                                  ;
main.c: In function 'main':
main.c:19:34: error: passing argument 4 of 'qsort' from incompatible pointer type [-Wincompatible-pointer-types]
   19 |         qsort(A, N, sizeof(int), compar_int);
      |                                  ^~~~~~~~~~
      |                                  |
      |                                  int (*)(int *, int *)
In file included from main.c:2:
/usr/include/stdlib.h:971:34: note: expected '__compar_fn_t' {aka 'int (*)(const void *, const void *)'} but argument is of type 'int (*)(int *, int *)'
  971 |                    __compar_fn_t __compar) __nonnull ((1, 4));
      |                    ~~~~~~~~~~~~~~^~~~~~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for( int i = 0; i < n; i++ )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define INF2 1000000000000000000

int main(void)
{
    int N;
    cin >> N;
    ll A[N];
    vector<int> B;
    rep(i ,N) cin >> A[i];
    sort(A, A + N, greater<int>());
    rep(i, N-1){
        if(A[i] == A[i+1]){
            B.push_back(A[i]);
            i++
        }
    }
    if(B.size() < 2){
        cout << 0 << endl;
        return 0;
    }
    cout << B[0] * B[1] << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:20:16: error: expected ';' before '}' token
   20 |             i++
      |                ^
      |                ;
   21 |         }
      |         ~
Language: Java


import java.util.Arrays;
import java.util.Scanner; 
public class CF {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		
		for(int i=0; i<n; i++) {
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		int side1 = 0, side2 = 0;
		for(int i=1; i<n; i++) {
			if(arr[i] == arr[i-1]) {
				side1 = side2;
				side2 = arr[i];
				i++;
			}
		}
		System.out.println((long) side1 * side2);
	}
}


Compiler output:
Main.java:4: error: class CF is public, should be declared in a file named CF.java
public class CF {
       ^
1 error
Language: C++

#include <iostream>
#include <algorithm>
#include <map>
#include <xfunctional>
using namespace std;

int main() {
	int n;
	cin >> n;
	map<int, int, greater<int>> m;
	for (int i = 0; i < n; i++) {
		int tm; cin >> tm;
		m[tm]++;
	}
	long long ans = 0;
	map<int, int>::iterator iter = m.begin();
	int one = 0, two = 0;
	while (iter != m.end()) {
		if (iter->second >= 2) {
			one = iter->first;
			iter->second -= 2;
			break;
		}
		iter++;
	}
	while (iter != m.end()) {
		if (iter->second >= 2) {
			two = iter->first;
			iter->second -= 2;
			break;
		}
		iter++;
	}
	ans = max(ans, 1ll * one * two);
	cout << ans << endl;
}

Compiler output:
a.cc:4:10: fatal error: xfunctional: No such file or directory
    4 | #include <xfunctional>
      |          ^~~~~~~~~~~~~
compilation terminated.
Language: C++

#include <iostream>
#include <map>
#include <vector>
using namespace std;

int main(){
	int N;
	cin >> N;
	vector<int> A(N);
	for(int i = 0 ; i < N ; i++) cin >> A[i];
	sort(A.rbegin(),A.rend());
	map<int,int> c;
	vector<long long> a(4);

	for(int i = 0 ; i < A.size() ; i++){
		c[A[i]]++;
		if( c[A[i]] >= 2){
			c[A[i]] -= 2;
			a.push_back(A[i]);
		}
	}
	sort(a.rbegin(),a.rend());
	cout << a[0] * a[1] << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:11:9: error: 'sort' was not declared in this scope; did you mean 'short'?
   11 |         sort(A.rbegin(),A.rend());
      |         ^~~~
      |         short
Language: C++

                                      /*  ***  In The Name of God ... ***  */
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll N = 1e5 + 10;

int n ;
map < int , int > cnt;
vector < int > vec;

int main ()
{
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin >> n;
	for(int i = 0 ; i < n ; i++)
	{
		int x;
		cin >> x;
		cnt[x]++;
		if(cnt[x] >= 2)
			vec.pb(x);
	}
	sort(vec.begin() , vec.end());
	reverse(vec.begin() , vec.end());
	if(vec.size() < 2)
		return cout << 0 , 0;
	cout << vec[0] * vec[1] << '\n';
	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:24:29: error: 'class std::vector<int>' has no member named 'pb'
   24 |                         vec.pb(x);
      |                             ^~
Language: Java

import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] A = new int[n];
		for(int i=0; i<n; i++) {
			A[i] = sc.nextInt();
		}
		sc.close();
		Arrays.sort(A);
		long l1 = 0;
		long l2 = 0;
		for(int i=n-1; i>=1; i--) {
			if(A[i]==A[i-1]) {
				if(l1==0) {
					l1 = A[i];
					i--;
				} else {
					l2 = A[i];
					break;
				}
			}
		}
		System.out.println(s);
	}
}

Compiler output:
Main.java:29: error: cannot find symbol
		System.out.println(s);
		                   ^
  symbol:   variable s
  location: class Main
1 error
Language: C++

#include <iostream>
#include <algorithm>
#include <vector>
 
using namespace std;
 
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
 
int k;
cin>>k;
vector<long long> all(k);
long long res=0;
for(int i=0;i<k;i++)
cin>>all[n];
 
sort(all.begin(),all.end());
 
long long a=0,b=0,tmp=-1;
for(int i=k-1;i>=0;i--)
{
if(tmp==all[i])
{
if(a==0)
{
a=tmp;
tmp=0;
}
else
{
b=tmp;
break;
}
}
else
tmp=all[i];
}
if(a*b>res)
res=a*b;
cout<<res<<endl;
 
return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:10: error: 'n' was not declared in this scope
   17 | cin>>all[n];
      |          ^
Language: C++

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

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

int k;
cin>>k;
vector<long long> all(k);
long long res=0;
for(int i=0;i<k;i++)
cin>>all[n];

sort(all,begin(),all.end());

long long a=0,b=0,tmp=-1;
for(int i=k-1;i>=0;i--)
{
if(tmp==all[i])
{
if(a==0)
{
a=tmp;
tmp=0;
}
else
{
b=tmp;
break;
}
}
else
tmp=all[i];
}
if(a*b>res)
res=a*b;
cout<<res<<endl;

return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:10: error: 'n' was not declared in this scope
   17 | cin>>all[n];
      |          ^
a.cc:19:15: error: no matching function for call to 'begin()'
   19 | sort(all,begin(),all.end());
      |          ~~~~~^~
In file included from /usr/include/c++/14/bits/range_access.h:36,
                 from /usr/include/c++/14/string:53,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/initializer_list:88:5: note: candidate: 'template<class _Tp> constexpr const _Tp* std::begin(initializer_list<_Tp>)'
   88 |     begin(initializer_list<_Tp> __ils) noexcept
      |     ^~~~~
/usr/include/c++/14/initializer_list:88:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:52:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.begin()) std::begin(_Container&)'
   52 |     begin(_Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
/usr/include/c++/14/bits/range_access.h:52:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:63:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.begin()) std::begin(const _Container&)'
   63 |     begin(const _Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
/usr/include/c++/14/bits/range_access.h:63:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:95:5: note: candidate: 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::begin(_Tp (&)[_Nm])'
   95 |     begin(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~~~
/usr/include/c++/14/bits/range_access.h:95:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:113:31: note: candidate: 'template<class _Tp> _Tp* std::begin(valarray<_Tp>&)'
  113 |   template<typename _Tp> _Tp* begin(valarray<_Tp>&) noexcept;
      |                               ^~~~~
/usr/include/c++/14/bits/range_access.h:113:31: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:114:37: note: candidate: 'template<class _Tp> const _Tp* std::begin(const valarray<_Tp>&)'
  114 |   template<typename _Tp> const _Tp* begin(const valarray<_Tp>&) noexcept;
      |                                     ^~~~~
/usr/include/c++/14/bits/range_access.h:114:37: note:   candidate expects 1 argument, 0 provided
Language: C++

#include <stdio.h>
#include<bits/stdc++.h>
#define ll long long
#define fr first
#define sc second
#define ii pair < int , int >
#define mp make_pair
using namespace std;
int main()
{
  int n;
  cin>>n;
  int a[n];
  for(int i=0;i<n;i++)
  {
      scanf("%d",&a[i]);
  }
  ll last1  = 0 , last2 = 0;
  sort(a,a+n);
  map < int , int > my;
  for(int i=n-1;i>=0;i--)
  {
      my[a[i]]++;
      if(my[a[i]] == 2 ||my[a[i]] == 4 )
      {
          if(!last1)
          last1 = a[i];
          else if(!last2)
            last2 = a[i];
      }
     
  }
  cout<<las1*las2;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:33:9: error: 'las1' was not declared in this scope; did you mean 'last1'?
   33 |   cout<<las1*las2;
      |         ^~~~
      |         last1
a.cc:33:14: error: 'las2' was not declared in this scope; did you mean 'last2'?
   33 |   cout<<las1*las2;
      |              ^~~~
      |              last2
Language: C++

#include <algorithm>
#include <vector>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;

int main()
{
  int N;
  cin >> N;
  vector<int> A(N);
  rep(i,N) cin >> A[i];

  sort(A.begin(), A.end(), greater<int>());

  int cnt = 1;
  int long1 = 0, long2 = 0;

  for(int i = 1; i < N; i++) {
    if(A[i] == A[i-1]) {
      cnt++;
    } else {
      cnt = 1;
    }

    if(cnt == 2) {
      if(long1 == 0) {
        long1 = A[i];
        cnt -= 2;
      } else {
        long2 = A[i];
        break;
      }
    }
  }

  cout << (long long)long1 * long2 << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:3: error: 'cin' was not declared in this scope
    9 |   cin >> N;
      |   ^~~
a.cc:3:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    2 | #include <vector>
  +++ |+#include <iostream>
    3 | #define rep(i,n) for(int i=0;i<n;i++)
a.cc:36:3: error: 'cout' was not declared in this scope
   36 |   cout << (long long)long1 * long2 << endl;
      |   ^~~~
a.cc:36:3: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:36:39: error: 'endl' was not declared in this scope
   36 |   cout << (long long)long1 * long2 << endl;
      |                                       ^~~~
a.cc:3:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    2 | #include <vector>
  +++ |+#include <ostream>
    3 | #define rep(i,n) for(int i=0;i<n;i++)
Language: Java

import java.io.*;
import java.util.*;

public class A {
    public static void main(String[] args) {
        InputReader in = new InputReader();
        PrintWriter out = new PrintWriter(System.out);
        int n = in.nextInt();
        TreeMap<Long, Integer> map = new TreeMap<>();
        for (int i = 0; i < n; i++) {
            long x = in.nextLong();
            if (map.get(x) == null) {
                map.put(x, 1);
            }
            else {
                map.put(x, map.get(x) + 1);
            }
        }

        long a = -1, b = -1;
        for (Map.Entry<Long, Integer> entry : map.entrySet()) {
            long key = entry.getKey();
            long value = entry.getValue();
            if (value >= 2) {
                if (a == -1 || b == -1) {
                    if (a == -1) a = key;
                    else b = key;
                }
                else {
                    if (a < b) {
                        a = key;
                    }
                    else b = key;
                }
            }
        }
        if (a == -1 || b == -1) {
            out.println(0);
        }
        else {
            out.println(a * b);
        }
        out.close();
    }

    static class InputReader {
        BufferedReader br;
        StringTokenizer st;

        public InputReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
}




Compiler output:
Main.java:4: error: class A is public, should be declared in a file named A.java
public class A {
       ^
1 error
Language: C++

We have a board with an H×W grid. Each square in the grid is painted in black or white. The square at the i-th row from the top and j-th column from the left is black if the j-th character in Si is #, and white if that character is ..

Snuke can perform the following operation on the grid any number of times:

Select a row or column in the grid, and invert the color of all the squares in that row or column (that is, black squares become white and vice versa).
Then, Snuke draws a rectangle along grid lines. Here, all the squares contained in the rectangle must be painted in black.

Find the maximum possible area of Snuke's rectangle when the operation is performed optimally.

Compiler output:
a.cc:1:25: error: extended character × is not valid in an identifier
    1 | We have a board with an H×W grid. Each square in the grid is painted in black or white. The square at the i-th row from the top and j-th column from the left is black if the j-th character in Si is #, and white if that character is ..
      |                         ^
a.cc:1:199: error: stray '#' in program
    1 | We have a board with an H×W grid. Each square in the grid is painted in black or white. The square at the i-th row from the top and j-th column from the left is black if the j-th character in Si is #, and white if that character is ..
      |                                                                                                                                                                                                       ^
a.cc:8:40: warning: missing terminating ' character
    8 | Find the maximum possible area of Snuke's rectangle when the operation is performed optimally.
      |                                        ^
a.cc:8:40: error: missing terminating ' character
    8 | Find the maximum possible area of Snuke's rectangle when the operation is performed optimally.
      |                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:1:1: error: 'We' does not name a type
    1 | We have a board with an H×W grid. Each square in the grid is painted in black or white. The square at the i-th row from the top and j-th column from the left is black if the j-th character in Si is #, and white if that character is ..
      | ^~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(int argc, char** argv) {
	long long n;
	cin>>n;
	long long  a[n]={0};
	 	long long  count[n]={0};
	 	long long t=0;
	for(int i=0;i<n;i++) {
		cin>>a[i];
	}
   sort(a,a+n);

   long long t1=0,t2=0,t3=0;
   long long x=0,y=0;
   bool k1=false,k2=false;
   for(int i=n-1;i>0;i--){
   	
   	if(a[i]==a[i-1]){
   		t1=a[i];
   		x=i;
   		k1=true;
		break;
	   }
   	
   }
   for(int i=n-1;i>0;i--){

	   if(k1){
	   
	   for(int i=n-1;i>0;i--){
   	if(a[i]==a[i-1]&&i!=x&&i!=(x-1)){
   		t2=a[i];
   		y=i;
   		k2=true;
		  break;	
	   }  }
   }
   if(k1&&k2)cout<<t1*t2<<endl;
 else  cout<<"0";
	return 0;
}

Compiler output:
a.cc: In function 'int main(int, char**)':
a.cc:42:2: error: expected '}' at end of input
   42 | }
      |  ^
a.cc:3:33: note: to match this '{'
    3 | int main(int argc, char** argv) {
      |                                 ^
Language: C++

#include <cstdio>
#include <cstring>
#include <cmath>
#include <map>
#include <stack>
#include <algorithm>
using namespace std;
const int Max = 2e5;
 
int n, a[Max + 5], l, r;
long long ans;
map<int, int> cnt;

bool cmp(int m, int n){
	return m > n;
}
 
int main()
{
	scanf ("%d", &n);
	for (int i = 1; i <= n; i++){
		scanf ("%d", &a[i]);
		cnt[a[i]]++;
	}
	l = 0;
	r = 0;
	sort(a + 1, a + n + 1, cmp);
	for (int i = 1; i <= n; i++){
		if (cnt[a[i]] >= 2){
			if (!l)	l = a[i], cnt[a[i]]-=2;
			else r = a[i];
			if (l && r)	break;
		}
	}
	ans = (LL)l * r;
	printf ("%I64d\n", ans);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:35:16: error: 'LL' was not declared in this scope
   35 |         ans = (LL)l * r;
      |                ^~
Language: C++

#include <iostream>
#include <fstream>
#include <cstdio>
#include <cassert>
#include <complex>
#include <cmath>
#include <algorithm>
#include <vector>
#include <string>
#include <cstdlib>
#include <cstring>
#include <iomanip>
#include <numeric>
#include <sstream>
#include <ctime>
#include <cctype>
#include <set>
#include <map>
#include <queue>
#include <bitset>
#include <deque>
#include <stack>
#include <memory.h>
using namespace std;
#define ll long long 
using namespace std;
typedef long long ll;
const int maxn = 1000000 + 10;
int n;
ll a[maxn]; 
int main()
{
    scanf("%d", &n);
    for(int i = 0; i < n; i++)
    {
        scanf("%lld", &a[i]);
    }
    sort(a, a + n);
    int x, y;
    bool fg1 = false, fg2 = false;
    for(int i = n-1; i > 0; i--)
    {
        if(a[i] == a[i-1])
        {
            x = i;
            fg1 = true;
            break;
        }
    }
    if(fg1)
    {
        for(int i = n-1; i > 0; i--)
        {
            if(a[i] == a[i-1] && i != x && i != (x-1))
            {
                y = i;
                fg2 = true;
                break;
            }
        }
    }
    if(fg1 && fg2)
    {
        ll ans = a[x] * a[y];
        printf("%lld\n", ans);
    }
    else printf("0\n");
    return 0;
}

Compiler output:
a.cc:25:12: error: 'long long long' is too long for GCC
   25 | #define ll long long
      |            ^~~~
a.cc:27:19: note: in expansion of macro 'll'
   27 | typedef long long ll;
      |                   ^~
a.cc:25:17: error: 'long long long' is too long for GCC
   25 | #define ll long long
      |                 ^~~~
a.cc:27:19: note: in expansion of macro 'll'
   27 | typedef long long ll;
      |                   ^~
a.cc:25:17: error: declaration does not declare anything [-fpermissive]
   25 | #define ll long long
      |                 ^~~~
a.cc:27:19: note: in expansion of macro 'll'
   27 | typedef long long ll;
      |                   ^~
Language: C++

#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
vector<int>vec[30];
string str,sub;

int fin(string tmp){
	int pos=-1;
	for(int i=0;i<tmp.length();i++){
		char ch=tmp[i];
		int nc=ch-'a';
		vector<int>::iterator np=upper_bound(vec[nc].begin(),vec[nc].end(),pos);
		if(np==vec[nc].end()){
			return 1;
		}else{
			pos=*np;
		}
	}
	return 0;
}

void bfs(){
	queue<string>que;
	while(!que.empty())que.pop();
	for(string ss="a";ss!="z";ss[ss.length()-1]++){
		que.push(ss);
	}
	que.push("z");
	while(!que.empty()&&que.size<100000){
		string tmp=que.front();
		//cout<<tmp<<endl;
		que.pop();
		if(fin(tmp)){
			//返回1找不到 
			sub=tmp;
			return ;
		}
		for(string ss="a";ss!="z";ss[ss.length()-1]++){
			que.push(tmp+ss);
		}
		que.push(tmp+"z");
	}
	
}

int main(){
	
	cin>>str;
	for(int i=0;i<30;i++){
		vec[i].clear(); 
	}
	for(int i=0;i<str.length();i++){
		vec[str[i]-'a'].push_back(i);
	}
	bfs();
	cout<<sub<<endl;
}

Compiler output:
a.cc: In function 'void bfs()':
a.cc:32:33: error: invalid use of member function 'std::queue<_Tp, _Sequence>::size_type std::queue<_Tp, _Sequence>::size() const [with _Tp = std::__cxx11::basic_string<char>; _Sequence = std::deque<std::__cxx11::basic_string<char>, std::allocator<std::__cxx11::basic_string<char> > >; size_type = long unsigned int]' (did you forget the '()' ?)
   32 |         while(!que.empty()&&que.size<100000){
      |                             ~~~~^~~~
      |                                     ()
Language: C++

#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */
#include<bits/stdc++.h>
using namespace std;
int main(int argc, char** argv) {
	long long n;
	cin>>n;
	long long  a[n]={0};
	 	long long  count[n]={0};
	 	long long t=0;
	for(int i=0;i<n;i++) {
		cin>>a[i];
	}
   sort(a,a+n);

   long long t1=0,t2=0,t3=0;
   for(int i=n-1;i>0;i--){
   	
   	if(a[i]==a[i-1]){
   		t1=a[i];
		break;
	   }
   	
   }
   for(int i=n-1;i>0;i--){

	   if(a[i]<t1){
	   
   	if(a[i]==a[i-1]){
   		t2=a[i];
		  break;	
	   }  }
   }
   for(int i=n-1;i>=3;i--){
   	if(a[i]==a[i-1]==a[i-2]==a[i-3]){
	   
   	   t3=a[i];
   	   break;}
   }
   long long k1=t3*t3;
   long long k2=t1*t2;
 if(k1>k2)cout<<k1;
 else if(k1<k2)  cout<<k2;
 else if(k1==k2)  cout<<k1;
 else  cout<<"0";
	return 0;
}#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */
#include<bits/stdc++.h>
using namespace std;
int main(int argc, char** argv) {
	long long n;
	cin>>n;
	long long  a[n]={0};
	 	long long  count[n]={0};
	 	long long t=0;
	for(int i=0;i<n;i++) {
		cin>>a[i];
	}
   sort(a,a+n);

   long long t1=0,t2=0,t3=0;
   for(int i=n-1;i>0;i--){
   	
   	if(a[i]==a[i-1]){
   		t1=a[i];
		break;
	   }
   	
   }
   for(int i=n-1;i>0;i--){

	   if(a[i]<t1){
	   
   	if(a[i]==a[i-1]){
   		t2=a[i];
		  break;	
	   }  }
   }
   for(int i=n-1;i>=3;i--){
   	if(a[i]==a[i-1]==a[i-2]==a[i-3]){
	   
   	   t3=a[i];
   	   break;}
   }
   long long k1=t3*t3;
   long long k2=t1*t2;
 if(k1>k2)cout<<k1;
 else if(k1<k2)  cout<<k2;
 else if(k1==k2)  cout<<k1;
 else  cout<<"0";
	return 0;
}

Compiler output:
a.cc:48:2: error: stray '#' in program
   48 | }#include <iostream>
      |  ^
a.cc:48:3: error: 'include' does not name a type
   48 | }#include <iostream>
      |   ^~~~~~~
a.cc:53:5: error: redefinition of 'int main(int, char**)'
   53 | int main(int argc, char** argv) {
      |     ^~~~
a.cc:6:5: note: 'int main(int, char**)' previously defined here
    6 | int main(int argc, char** argv) {
      |     ^~~~
Language: C++

#include<stdio.h>
#include<iostream>
using namespace std;
int a[100010];
bool cmp(int x,int y)
{
	return x>y;
}
int main()
{
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		scanf("%d",&a[i]);
	}
	sort(a,a+n,cmp);
	long long s=1;
	int p=0,k=1;
	for(int i=0;i<n-1;i++)
	{
		if(a[i]==a[i+1])
		{
			k++;
		}
		else
		{
			if(k>=2&&k<4)
			{
				s*=a[i];
				p++;
			}
			if(k==4)
			{
				s=a[i]*a[i];
				p=2;
			}
			if(p==2)
			{
				break;
			}
			k=1;
		}
		if(i==n-2&&k==2)
		{
			s*=a[i];
			p++;
		}
		if(i==n-2&&k==4)
		{
			s=a[i]*a[i];
			p=2;
		}
	}
	if(p==2)
		printf("%lld\n",s);
	else
		printf("0\n");
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:9: error: 'sort' was not declared in this scope; did you mean 'short'?
   17 |         sort(a,a+n,cmp);
      |         ^~~~
      |         short
Language: C++

#include<stdio.h>
#include<iostream>
using namespace std;
int a[100010];
bool cmp(int x,int y)
{
	return x>y;
}
int main()
{
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		scanf("%d",&a[i]);
	}
	sort(a,a+n,cmp);
	long long s=1;
	int flag=0,p=0,k=1;
	for(int i=0;i<n-1;i++)
	{
		if(a[i]==a[i+1])
		{
			k++;
		}
		else
		{
			if(k>=2&&k<4)
			{
				s*=a[i];
				p++;
			}
			if(k==4)
			{
				s=a[i]*a[i];
				p=2;
			}
			if(p==2)
			{
				break;
			}
			k=1;
		}
		if(i==n-2&&k==2)
		{
			s*=a[i];
			p++;
		}
		if(i==n-2&&k==4)
		{
			s=a[i]*a[i];
			p=2;
		}
	}
	if(p==2)
		cout<<s<<endl;
	else
		printf("0\n");
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:9: error: 'sort' was not declared in this scope; did you mean 'short'?
   17 |         sort(a,a+n,cmp);
      |         ^~~~
      |         short
Language: C++

#include<stdio.h>
#include<iostream>
#include<queue>
using namespace std;
int a[100010];
bool cmp(int x,int y)
{
	return x>y;
}
int main()
{
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		scanf("%d",&a[i]);
	}
	sort(a,a+n,cmp);
	long long s=1,x=0,y=0;
	int flag=0,p=0,k=1;
	for(int i=0;i<n-1;i++)
	{
		if(a[i]==a[i+1])
		{
			k++;
		}
		else
		{
			if(k>=2&&k<4)
			{
				s*=a[i];
				p++;
			}
			if(k==4)
			{
				s=a[i]*a[i];
				p=2;
			}
			if(p==2)
			{
				break;
			}
			k=1;
		}
		if(i==n-2&&k==2)
		{
			s*=a[i];
			p++;
		}
		if(i==n-2&&k==4)
		{
			s=a[i]*a[i];
			p=2;
		}
	}
	if(p==2)
		cout<<s<<endl;
	else
		printf("0\n");
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:9: error: 'sort' was not declared in this scope; did you mean 'short'?
   18 |         sort(a,a+n,cmp);
      |         ^~~~
      |         short
Language: C++

#include<cstdio>
#include<cstring>
#include<map>
using namespace std;
map<long long int, int> mp;
long long int rem[100100];
int cnt;
int main(){
    int n,x;
    scanf("%d",&n);
    for(int i = 1; i <= n; i ++){
        scanf("%d",&x);
        if(!mp[x])
            rem[++cnt] = x;
        mp[x] ++;
    }
    long long int a = 0, ans = 0;
    sort(rem+1, rem+1+cnt);
    for(int i = cnt; i >= 1; i --){
        if(mp[rem[i]] >= 4){
            ans = rem[i] * rem[i];
            break;
        }
        else if(mp[rem[i]] > 1 && a){
            ans = rem[i] * a;
            break;
        }
        else if(mp[rem[i]] > 1){
            a = rem[i];
            continue;
        }
    }
    printf("%lld",ans);
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:5: error: 'sort' was not declared in this scope; did you mean 'short'?
   18 |     sort(rem+1, rem+1+cnt);
      |     ^~~~
      |     short
Language: C++

#include<cstdio>
#include<cstring>
#include<map>
using namespace std;
map<long long int, int> mp;
long long int rem[100100];
int cnt;
int main(){
    int n,x;
    scanf("%d",&n);
    for(int i = 1; i <= n; i ++){
        scanf("%lld",&x);
        if(!mp[x])
            rem[++cnt] = x;
        mp[x] ++;
    }
    long long int a = 0, ans = 0;
    sort(rem+1, rem+1+cnt);
    for(int i = cnt; i >= 1; i --){
        if(mp[rem[i]] >= 4){
            ans = rem[i] * rem[i];
            break;
        }
        else if(mp[rem[i]] > 1 && a){
            ans = rem[i] * a;
            break;
        }
        else if(mp[rem[i]] > 1){
            a = rem[i];
            continue;
        }
    }
    printf("%lld",ans);
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:5: error: 'sort' was not declared in this scope; did you mean 'short'?
   18 |     sort(rem+1, rem+1+cnt);
      |     ^~~~
      |     short
Language: C++

//arc081 q1
#include <cstdio>
#include <algorithm>
#include <queue>
#include <stack>
#include <vector>
#include <string>
#include <cmath>
#include <map>
#include <set>
#include <iostream>
#include <tuple>
#include <deque>
#define pb push_back
#define pf push_front
#define mkt make_tuple
#define pqueue priority_queue
using namespace std;
typedef long long int ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
const int INF =  2147483647;
const ll INFLL = 9223372036854775807;

map<ll, ll> cache;


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

  ll n, a, h = 0, w = 0, ans;
  cin >> n;
  for (size_t i = 0; i < n; i++) {
    cin >> a;
    cache[a]++;
    ll num = cache[a];
    if ((num == 2 || num == 4) && num => h && num => w) {
      h = max(h, w);
      w = a;
    }
  }

  ans = h * w;

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


Compiler output:
a.cc: In function 'int main()':
a.cc:41:40: error: expected primary-expression before '>' token
   41 |     if ((num == 2 || num == 4) && num => h && num => w) {
      |                                        ^
a.cc:41:52: error: expected primary-expression before '>' token
   41 |     if ((num == 2 || num == 4) && num => h && num => w) {
      |                                                    ^
Language: C++

#include <cstdio>
#include <iostream>
#include <cstring>
#include <string>
#include <cmath>
#include <queue>
#include <set>
#include <map>
#include <complex>
#include <algorithm>
#include <vector>
using namespace std;
typedef long long ll;
typedef long double db;
typedef pair<int,int> pii;
typedef vector<int> vi;
#define de(x) cout << #x << "=" << x << endl
#define rep(i,a,b) for(int i=a;i<(b);++i)
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define IO(x) freopen(x".in", "r", stdin); freopen(x".out", "w", stdout);
const int INF = 0x3f3f3f3f;
const int maxn=1e5+7;
int a[maxn];
bool cmp(int a,int b) { return a>b; }
int main()
{
	int n;
	scanf("%d",&n);
	for(int i=1;i<=n;i++) scanf("%d",&a[i]);
	sort(a+1,a+n+1,cmp);
	int len=0,wid=0;
	for(int i=1;i<n;i++)
	{
		if(a[i]==a[i+1]) 
		{
			if(len==0) {len=a[i]; i++; continue;}
			else { wid=a[i]; break; } 
		}
	}
	__int64 ans;
//	de(len);
//	de(wid);
	ans=(__int64)len*(__int64)wid;
    cout<<ans<<endl;
	
	return 0;
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:45:9: error: '__int64' was not declared in this scope; did you mean '__ynf64'?
   45 |         __int64 ans;
      |         ^~~~~~~
      |         __ynf64
a.cc:48:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   48 |         ans=(__int64)len*(__int64)wid;
      |         ^~~
      |         abs
Language: C++

#include<iostream>
#include<string.h>
#include<algorithm>
using namespace std;
int main(){
    int n;
    cin>>n;
    long long int input[n];
    long long int ma[2];
    ma[0]=0;
    ma[1]=0;
    for(int i=0;i<n;i++){
        cin>>input[i];
    }

    sort(input,input+n);
    reverse(input,input+n);
    int now=0;
    while(now<2&&i<n){
    for(int i=1;i<n;i++){
        if(input[i]==input[i-1]){
            ma[now]=input[i];
            i++;
            now++;
        }
    }
    }

    cout<<ma[0]*ma[1];
    }
~

Compiler output:
a.cc: In function 'int main()':
a.cc:19:18: error: 'i' was not declared in this scope
   19 |     while(now<2&&i<n){
      |                  ^
a.cc: At global scope:
a.cc:31:2: error: expected class-name at end of input
   31 | ~
      |  ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(int argc, char** argv) {
	int n;
	cin>>n;
	int a[n]={0};
	int count[n]={0};
	for(int i=0;i<n;i++) {
		cin>>a[i];
	}
   sort(a,a+n);
   long long t1=0,T1,t2=0,T2;
   for(int i=0;i<n-1;i++){
   	
   	if(a[i]==a[i+1]){
   		t1=a[i];
		break;
	   }
   	
   }
   for(int i=0;i<n-1;i++){

	   
   	if(a[i]==a[i+1]&&a[i]<t1){
   		t2=a[i];
		  	break;
	   }
   }
   }
   if(t1==0||t2==0)  cout<<"0"<<endl;;
    if(t1!=0&&t2!=0)cout<<t1*t2<<endl;
	return 0;
}

Compiler output:
a.cc:30:4: error: expected unqualified-id before 'if'
   30 |    if(t1==0||t2==0)  cout<<"0"<<endl;;
      |    ^~
a.cc:31:5: error: expected unqualified-id before 'if'
   31 |     if(t1!=0&&t2!=0)cout<<t1*t2<<endl;
      |     ^~
a.cc:32:9: error: expected unqualified-id before 'return'
   32 |         return 0;
      |         ^~~~~~
a.cc:33:1: error: expected declaration before '}' token
   33 | }
      | ^
Language: C++

#include<algorithm>
#include<vector>
#include<map>
using namespace std;

int main() {
    int N, i, a;
    map<int, int>A;
    vector<int> v;
    cin >> N;
    for (i = 0; i < N; i++) {
        cin >> a;
        A[a]++;
        if (A[a] % 2 == 0) {
            v.push_back(a);
        }
    }

    if (v.size() < 2) {
        cout << 0 << endl;
        return 0;
    }
    sort(v.begin(), v.end(), greater<int>());

    cout << v[0] * v[1] << endl;
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:5: error: 'cin' was not declared in this scope
   10 |     cin >> N;
      |     ^~~
a.cc:4:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    3 | #include<map>
  +++ |+#include <iostream>
    4 | using namespace std;
a.cc:20:9: error: 'cout' was not declared in this scope
   20 |         cout << 0 << endl;
      |         ^~~~
a.cc:20:9: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:20:22: error: 'endl' was not declared in this scope
   20 |         cout << 0 << endl;
      |                      ^~~~
a.cc:4:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    3 | #include<map>
  +++ |+#include <ostream>
    4 | using namespace std;
a.cc:25:5: error: 'cout' was not declared in this scope
   25 |     cout << v[0] * v[1] << endl;
      |     ^~~~
a.cc:25:5: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:25:28: error: 'endl' was not declared in this scope
   25 |     cout << v[0] * v[1] << endl;
      |                            ^~~~
a.cc:25:28: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
Language: C++

#include<iostream>
using namespace std;
#include<algorithm>
#include<cmath>
#define N 100010
long long a[N];
int main()
{
	int n,i,k,j;
	long long tempa,tempb;
	while(cin>>n){
		tempa=0;
		tempb=0;
		k=0;
		memset(a,0,sizeof(a));
		for(i=0;i<n;i++)
			cin>>a[i];
		sort(a,a+n);
		for(i=n-1;i>=1;i--)
			if(a[i]==a[i-1])
			{
				tempa=a[i];
				k=i-1;
				break;
			}
		for(j=k-1;j>=1;j--)
			if(a[j]==a[j-1])
			{
				tempb=a[j];
				break;
			}
			printf("%lld\n",tempa*tempb);
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:15:17: error: 'memset' was not declared in this scope
   15 |                 memset(a,0,sizeof(a));
      |                 ^~~~~~
a.cc:5:1: note: 'memset' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    4 | #include<cmath>
  +++ |+#include <cstring>
    5 | #define N 100010
Language: C++

#include <iostream>
#include <map>
using namespace std;

int N;
int A[100000+5];

int main()
{
    cin.sync_with_stdio(false);
    cin >> N;
    // map<int, int> counts;
    // int t = 0;
    for (int i = 0; i < N; ++i)
    {
        // cin >> t;
        // counts[t]++;
        cin >> A[i];
    }

    // int w = 0, h = 0;
    // for (auto& p : counts)
    // {
    //     int a = p.first;
    //     int c = p.second;
    //     if (c >= 2)
    //     {
    //         if (c > w)
    //         {

    //         }
    //     }
    // }

    sort(A, A+N);

    int w = 0;
    int h = 0;
    int i = N-1;
    while (i >= 1)
    {
        if (A[i] == A[i-1])
        {
            w = A[i];
            i -= 2;
            break;
        }
        i--;
    }

    if (w == 0)
    {
        cout << 0 << endl;
        return 0;
    }

    while (i >= 1)
    {
        if (A[i] == A[i-1])
        {
            h = A[i];
            break;
        }
        i--;
    }

    cout << w*h << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:35:5: error: 'sort' was not declared in this scope; did you mean 'short'?
   35 |     sort(A, A+N);
      |     ^~~~
      |     short