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

#include<stdio.h>
#include<algorithm>
using namespace std;
typedef long long ll;
ll s[100000];
bool cmp(ll a,ll b)
{
	return a>b;
}
int main()
{
	int n;
	while(scanf("%d",&n)!=EOF) {
		for(int i=0; i<n; i++) {
			scanf("%lld",&s[i]);
		}
		sort(s,s+n,cmp);
		int x=0,y=0;
		for(int i=0; i<n-4; i++) {
			if(s[i]==s[i+1] && s[i+1]==s[i+2] && s[i+2]==s[i+3]) {
				x=y=s[i];
			} else if(s[i]==s[i+1] && s[i+1]==s[i+2] && s[i+2]!=s[i+3]) {
				if(!x) {
					x=s[i];
				} else {
					y=s[i];
				}
			}else if(s[i]==s[i+1] && s[i+1]!=s[i+2]){
				if(!x) {
					x=s[i];
				} else {
					y=s[i];
				}
			}
		}
		ll max=x*y;
		printf("%lld\n",max);
	}
	return 0;
}

Compiler output:
main.c:2:9: fatal error: algorithm: No such file or directory
    2 | #include<algorithm>
      |         ^~~~~~~~~~~
compilation terminated.
Language: C

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


typedef struct node {
  struct node *p;
  int x;
} LIST;
 LIST *a =NULL;

void add(int x){
 LIST *add = (LIST *)malloc(sizeof(LIST));
 LIST **p =&a;
 while(*p!=NULL){
  if((*p)->x > x) p=&((*p)->p);
 }
 add.x =x;
 add.p = *p;
 *p = add;
 return 0;
}

int get(){
 if(a==NULL) return -1;
 int x=a.x;
 LIST *p =a;
 a=a->p;
 free(p);
 return x;
}

int main()
{
 int x, y, a[100000]={0};
 int n, i;
 scanf("%d", &n);
 for(i=0; i<n; i++){
  scanf("%d", x);
  a[x]++;
  if(a[x] ==1)
   add(x);
 }
 if((x=get()) == -1){
  puts("0");
  return 0;
 }
 if((y=get(()==-1){
   puts("0");
  return 0;
 }
 printf("%d\n", x*y);
 while(get()!=-1);
 return 0;
}

Compiler output:
main.c: In function 'add':
main.c:17:5: error: 'add' is a pointer; did you mean to use '->'?
   17 |  add.x =x;
      |     ^
      |     ->
main.c:18:5: error: 'add' is a pointer; did you mean to use '->'?
   18 |  add.p = *p;
      |     ^
      |     ->
main.c:20:9: error: 'return' with a value, in function returning void [-Wreturn-mismatch]
   20 |  return 0;
      |         ^
main.c:11:6: note: declared here
   11 | void add(int x){
      |      ^~~
main.c: In function 'get':
main.c:25:9: error: 'a' is a pointer; did you mean to use '->'?
   25 |  int x=a.x;
      |         ^
      |         ->
main.c: In function 'main':
main.c:47:13: error: expected expression before ')' token
   47 |  if((y=get(()==-1){
      |             ^
main.c:47:19: error: expected ')' before '{' token
   47 |  if((y=get(()==-1){
      |     ~             ^
      |                   )
main.c:53:11: error: expected ')' before '}' token
   53 |  return 0;
      |           ^
      |           )
   54 | }
      | ~          
main.c:47:4: note: to match this '('
   47 |  if((y=get(()==-1){
      |    ^
main.c:54:1: error: expected expression before '}' token
   54 | }
      | ^
Language: C++


use std::io;
use std::cmp;
use std::collections::VecDeque;
use std::collections::HashMap;

fn main() {
    let stdin = io::stdin();
    let mut buf = String::new();
    stdin
        .read_line(&mut buf)
        .expect("ERROR Can't read array size");
    let n:usize = buf.trim().parse().unwrap();
    let mut buf = String::new();
    stdin
        .read_line(&mut buf)
        .expect("ERROR Can't read array size");
    let mut a: Vec<i64> = buf.split_whitespace()
        .map(|n| n.parse().unwrap())
        .collect();

    let mut edges = HashMap::new();

    for x in a.iter() {
        let val = edges.get(x).unwrap_or(&0) + 1;
        edges.insert(x, val);
    }

    let mut e1 = 0i64;
    let mut e2 = 0i64;
    for (&x,&y) in edges.iter() {
        if y >=4 {
            e1 = cmp::max(e1, *x);
            e2 = cmp::max(e2, *x);
        } else if y>=2 {
            if e1 < *x {
                e2 = e1;
                e1 = *x;
            } else if e2 < *x {
                e2 = *x;
            }
        }
    }
    println!("{}", e1*e2);

}


Compiler output:
a.cc:2:1: error: 'use' does not name a type
    2 | use std::io;
      | ^~~
a.cc:3:1: error: 'use' does not name a type
    3 | use std::cmp;
      | ^~~
a.cc:4:1: error: 'use' does not name a type
    4 | use std::collections::VecDeque;
      | ^~~
a.cc:5:1: error: 'use' does not name a type
    5 | use std::collections::HashMap;
      | ^~~
a.cc:7:1: error: 'fn' does not name a type
    7 | fn main() {
      | ^~
Language: C++

#include <iostream>
#include <string>

using namespace::std;

int N, A[10000];
int max, nmax;
bool m;
void sort(int a[], int total) {
	int tmp;
	for (int i = 0; i < total; i++) {
		for (int j = i + 1; j < total; j++) {
			if (a[i] < a[j]) {
				tmp = a[i];
				a[i] = a[j];
				a[j] = tmp;
			}
		}
	}

}
int main() {
	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> A[i];
	}
	nmax = 0;
	m = false;
	sort(A, N);
	for (int i = 0; i < N-1; i++) {
		if (!m) {
			if (A[i] == A[i + 1]) {
				max = A[i];
				i++;
				m = true;
			}
		}
		else {
		if (A[i] == A[i + 1]) {
			nmax = A[i];
			break;
			}
		}
	}
		cout << max*nmax;

	
		}



Compiler output:
a.cc: In function 'int main()':
a.cc:33:33: error: reference to 'max' is ambiguous
   33 |                                 max = A[i];
      |                                 ^~~
In file included from /usr/include/c++/14/string:51,
                 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/bits/stl_algobase.h:303:5: note: candidates are: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:                 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
a.cc:7:5: note:                 'int max'
    7 | int max, nmax;
      |     ^~~
a.cc:45:25: error: reference to 'max' is ambiguous
   45 |                 cout << max*nmax;
      |                         ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidates are: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:                 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
a.cc:7:5: note:                 'int max'
    7 | int max, nmax;
      |     ^~~
Language: C++

#include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <stdio.h>
#include <stdlib.h>
#include <string>
using namespace std;

int main() {

	vector<long long int> a;
	vector<long long int> saiyo;
	size_t n_count;
	long long n;

	scanf_s("%lld", &n);

	for (long long i = 0; i < n; i++) {
		long long tmp;
		scanf_s("%lld", &tmp);
		a.push_back(tmp);
	}

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

	long long oldValue;
	long long newValue;
	
	while (a.size() > 1) {
		oldValue = a.back();
		a.pop_back();
		newValue = a.back();
		if (oldValue == newValue) {
			//採用
			saiyo.push_back(oldValue);
			
			//二つ採用したらおしまい
			if (saiyo.size() == 2) {
				printf("%lld", saiyo[0] * saiyo[1]);
				return 0;
			}
			else {
				a.pop_back();
			}
		}
	}

	//おしまいにならず⇒作れない
	printf("0");
	return 1;

}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:9: error: 'scanf_s' was not declared in this scope; did you mean 'scanf'?
   17 |         scanf_s("%lld", &n);
      |         ^~~~~~~
      |         scanf
Language: C++

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

int main(){
    long long n;

    cin >> n;
    vector<long long>a(n);
    
    for(long long i; i < n; i++){
        cin >> a[i];
    }
    long long x =0;
    long long y = 0;
    long long ans = 0;
    for(long long i; i < n; i++){
        for(long long j; j < n; j++){
            if(a[i] == a[j]){
                x += x;
                ans = max(x,max);
                if(ans != x){
                    y += y;
                }
            }
        }
    }

    cout << ans * y << endl;

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:20:26: error: no matching function for call to 'max(long long int&, <unresolved overloaded function type>)'
   20 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
In file included 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_algobase.h:257:5: note: candidate: 'constexpr const _Tp& std::max(const _Tp&, const _Tp&) [with _Tp = long long int]'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:36: note:   no known conversion for argument 2 from '<unresolved overloaded function type>' to 'const long long int&'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |                         ~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:20:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   20 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
Language: C++

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

int main(){
    long long n;
    vector<long long>a(n);

    cin >> n;

    for(long long i; i < n; i++){
        cin >> a[i];
    }
    long long x =0;
    long long y = 0;
    long long ans = 0;
    for(long long i; i < n; i++){
        for(long long j; j < n; j++){
            if(a[i] == a[j]){
                x += x;
                ans = max(x,max);
                if(ans != x){
                    y += y;
                }
            }
        }
    }

    cout << ans * y << endl;

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:20:26: error: no matching function for call to 'max(long long int&, <unresolved overloaded function type>)'
   20 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
In file included 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_algobase.h:257:5: note: candidate: 'constexpr const _Tp& std::max(const _Tp&, const _Tp&) [with _Tp = long long int]'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:36: note:   no known conversion for argument 2 from '<unresolved overloaded function type>' to 'const long long int&'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |                         ~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:20:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   20 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
Language: C++

#include <iostream>
#include <vector>
#include <array>
#include <stdio.h>
#include <stdlib.h>
#include <string>
using namespace std;

int main() {

	vector<long long int> a;
	vector<long long int> saiyo;
	size_t n_count;
	long long n;

	scanf("%lld", &n);

	for (long long i = 0; i < n; i++) {
		long long tmp;
		scanf("%lld", &tmp);
		a.push_back(tmp);
	}

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

	long long oldValue;
	long long newValue;
	
	while (a.size() > 1) {
		oldValue = a.back();
		a.pop_back();
		newValue = a.back();
		if (oldValue == newValue) {
			//採用
			saiyo.push_back(oldValue);
			
			//二つ採用したらおしまい
			if (saiyo.size() == 2) {
				printf("%lld", saiyo[0] * saiyo[1]);
				return 0;
			}
			else {
				a.pop_back();
			}
		}
	}

	//おしまいにならず⇒作れない
	printf("0");
	return 0;

}

Compiler output:
a.cc: In function 'int main()':
a.cc:24:9: error: 'sort' was not declared in this scope; did you mean 'short'?
   24 |         sort(a.begin(), a.end());
      |         ^~~~
      |         short
Language: C++

#include <cstdio>
#include <vector>
#include <functional>

int main() {
    long n;
    std::vector<long> bou;
    scanf("%ld", &n);
    for (long i = 0; i < n; i++) {
        long a;
        scanf(" %ld", &a);
        bou.push_back(a);
    }
    std::sort(bou.begin(), bou.end(), std::greater<long>());
    long max1 = -1;
    long max2 = -1;
    for (auto itr = bou.begin(); itr !=bou.end(); itr++) {
        if (*itr == *(itr + 1)) {
            if (max1 == -1)
                max1 = *itr;
            else if (max2 == -1)
                max2 = *itr;
            else
                break;
            itr++;
        }
    }
    if (max2 == -1)
        puts("0");
    else
        printf("%d\n", max1 * max2);
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:10: error: 'sort' is not a member of 'std'
   14 |     std::sort(bou.begin(), bou.end(), std::greater<long>());
      |          ^~~~
Language: C++

#include <iostream>
#include <string>
#include <cmath>
#include <vector>

using namespace std;

int main(int argc, const char * argv[]) {
    int N;
    int length=0;
    cin>>N;
    
    int Ai[1000000000];
    
    
    for(int i=0;i<N;i++){
        int a;
        cin>>a;
        Ai[a]++;
    }
    
    for(int i=1000000000;i>=0;i--){
        if(Ai[i]=>4 && length==0){
            printf("%d",i*i);
            break;
        }
        if(Ai[i]>=2 && length==0){
            length=i;
        }
        else if(Ai[i]>=2 && length!=0){
            printf("%d",length*i);
            break;
        }
    }
    
    
    return 0;
}


Compiler output:
a.cc: In function 'int main(int, const char**)':
a.cc:23:18: error: expected primary-expression before '>' token
   23 |         if(Ai[i]=>4 && length==0){
      |                  ^
Language: C++

#include<cmath>
#include<cstdio>
#include<cstring>
#include<iomanip>
#include<iostream>
#include<algorithm>
using namespace std;
chengfa(int n,int m){
	int a[100],b[100],c[100],len,la,lb;
	la=0;
	while(n>0){
		la++;
		a[la]=n%10;
		n=n/10;
	}
	lb=0;
	while(m>0){
		lb++;
		b[lb]=m%10;
		m=m/10;
	}
	memset(c,0,sizeof(c));
	for(long long i=1;i<=la;i++)
	for(long long j=1;j<=lb;j++)
	c[i+j-1]=c[i+j-1]+a[i]*b[j];
	len=la+lb;
	for(long long i=1;i<=len;i++){
		c[i+1]=c[i+1]+c[i]/10;
		c[i]=c[i]%10;
	}
	while(c[len]==0){len--;}
	m=c[len];
	while(m>0){
		c[len]=m%10;
		m=m/10;
		len++;
	}
	for(long long i=len-1;i>=1;i--) 
		cout<<c[i];
}
int main(){
	long long N,a[100005],b[100005],j=1;
	memset(a,0,sizeof(a));
	memset(b,0,sizeof(b));
	cin>>N;
	for(long long i=1;i<=N;i++)
		cin>>a[i];
	sort(a+1,a+N+1);
	for(long long i=N;i>=1;i-=2){
		if(a[i]==a[i-1]){
			b[j]=a[i];
			j++;
		}
	}
	if(b[1]==0||b[2]==0){
		cout<<0<<endl;
		return 0;
	}
	chengfa(b[1],b[2]);
	return 0;
}

Compiler output:
a.cc:8:1: error: ISO C++ forbids declaration of 'chengfa' with no type [-fpermissive]
    8 | chengfa(int n,int m){
      | ^~~~~~~
a.cc: In function 'int chengfa(int, int)':
a.cc:40:1: warning: no return statement in function returning non-void [-Wreturn-type]
   40 | }
      | ^
Language: C++

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

int main(){
    long long n,a;

    cin >> n;

    for(long long i; i < n; i++){
        cin >> a[i];
    }
    long long x =0;
    long long y = 0;
    long long ans = 0;
    for(long long i; i < n; i++){
        for(long long j; j < n; j++){
            if(a[i] == a[j]){
                x += x;
                ans = max(x,max);
                if(ans != x){
                    y += y;
                }
            }
        }
    }

    cout << ans * y << endl;

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:17: error: invalid types 'long long int[long long int]' for array subscript
   10 |         cin >> a[i];
      |                 ^
a.cc:17:17: error: invalid types 'long long int[long long int]' for array subscript
   17 |             if(a[i] == a[j]){
      |                 ^
a.cc:17:25: error: invalid types 'long long int[long long int]' for array subscript
   17 |             if(a[i] == a[j]){
      |                         ^
a.cc:19:26: error: no matching function for call to 'max(long long int&, <unresolved overloaded function type>)'
   19 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
In file included 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_algobase.h:257:5: note: candidate: 'constexpr const _Tp& std::max(const _Tp&, const _Tp&) [with _Tp = long long int]'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:36: note:   no known conversion for argument 2 from '<unresolved overloaded function type>' to 'const long long int&'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |                         ~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:19:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   19 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
Language: C++

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

int main(){
    int n,a;

    cin >> n;

    for(int i; i < n; i++){
        cin >> a[i];
    }
    int x =0;
    int y = 0;
    int ans = 0;
    for(int i; i < n; i++){
        for(int j; j < n; j++){
            if(a[i] == a[j]){
                x += x;
                ans = max(x,max);
                if(ans != x){
                    y += y;
                }
            }
        }
    }

    cout << ans * y << endl;

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:17: error: invalid types 'int[int]' for array subscript
   10 |         cin >> a[i];
      |                 ^
a.cc:17:17: error: invalid types 'int[int]' for array subscript
   17 |             if(a[i] == a[j]){
      |                 ^
a.cc:17:25: error: invalid types 'int[int]' for array subscript
   17 |             if(a[i] == a[j]){
      |                         ^
a.cc:19:26: error: no matching function for call to 'max(int&, <unresolved overloaded function type>)'
   19 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
In file included 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_algobase.h:257:5: note: candidate: 'constexpr const _Tp& std::max(const _Tp&, const _Tp&) [with _Tp = int]'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:36: note:   no known conversion for argument 2 from '<unresolved overloaded function type>' to 'const int&'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |                         ~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:19:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   19 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
Language: C++

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

int main(){
    int n,a;

    cin >> n;

    for(int i; i < n; i++){
        cin >> a[i];
    }
    int x,y,ans = 0;
    for(int i; i < n; i++){
        for(int j; j < n; j++){
            if(a[i] == a[j]){
                x += x;
                ans = max(x,max);
                if(ans != x){
                    y += y;
                }
            }
        }
    }

    cout << ans * y << endl;

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:17: error: invalid types 'int[int]' for array subscript
   10 |         cin >> a[i];
      |                 ^
a.cc:15:17: error: invalid types 'int[int]' for array subscript
   15 |             if(a[i] == a[j]){
      |                 ^
a.cc:15:25: error: invalid types 'int[int]' for array subscript
   15 |             if(a[i] == a[j]){
      |                         ^
a.cc:17:26: error: no matching function for call to 'max(int&, <unresolved overloaded function type>)'
   17 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
In file included 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_algobase.h:257:5: note: candidate: 'constexpr const _Tp& std::max(const _Tp&, const _Tp&) [with _Tp = int]'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:36: note:   no known conversion for argument 2 from '<unresolved overloaded function type>' to 'const int&'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |                         ~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:17:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   17 |                 ans = max(x,max);
      |                       ~~~^~~~~~~
Language: C++

// c Make a rectangle

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

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	
	int n, t;
	cin>>n;
	
	int arr[n];
	
	for(int i=0;i<n;i++) cin>>arr[i];
	
    
    sort(arr,arr+n);
    
    int l = 0,b = 0;
    
    bool f1 = false, f2 = false;
    
    int i=n-1;

    while(i>=1){
        if(arr[i]==arr[i-1]){
            if(!f1){
                l = a[i];
                f1 = true;
                i--;
            }
            else if(!f2){
                b = a[i];
                f2 = true;
                i--;
            }
            else break;
        }
        i--;
    }
    
    long long ans = l*b;
    
    printf("%lld\n", ans);

	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:29:21: error: 'a' was not declared in this scope
   29 |                 l = a[i];
      |                     ^
a.cc:34:21: error: 'a' was not declared in this scope
   34 |                 b = a[i];
      |                     ^
Language: C++

#include <iostream>
using namespace std;

int main() 
{
    int n;
    long long a[100000];
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }

    long long max = 0, semimax = 0;
    int flag = 0;
    sort(a, a + n);
    for (int i = n - 1;i >= 0; i--) {
        if (a[i] == a[i-1]) {
            if (a[i] == max || a[i] == semimax) continue;
            if (flag == 0) {
                max = a[i];
                flag++;
            } else if (flag == 1) {
                semimax = a[i];
                flag++;
                break;
            }
        }
    }

    cout << max * semimax << endl;

    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:15:5: error: 'sort' was not declared in this scope; did you mean 'short'?
   15 |     sort(a, a + n);
      |     ^~~~
      |     short
Language: C++

#include<stdio.h>
#include<stdlib.h>
#include<algorithm>
#include<bitset>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<functional>
#include<list>
#include<map>
#include<iomanip>
#include<iostream>
#include<queue>
#include<set>
#include<stack>
#include<string>
#include<vector>
#include<algorithm>
#include<memory.h>
using namespace std;
chengfa(int n,int m){
	int a[100],b[100],c[100],len,la,lb,i,j;
	la=0;
	while(n>0)
	{
	la++;
	a[la]=n%10;
	n=n/10;
	}
	lb=0;
	while(m>0)
	{
	lb++;
	b[lb]=m%10;
	m=m/10;
	}
	memset(c,0,sizeof(c));
	for(i=1;i<=la;i++)
	for(j=1;j<=lb;j++)
	c[i+j-1]=c[i+j-1]+a[i]*b[j];
	len=la+lb;
	for(i=1;i<=len;i++)
	{
	c[i+1]=c[i+1]+c[i]/10;
	c[i]=c[i]%10;
	}
	while(c[len]==0){len--;}
	m=c[len];
	while(m>0)
	{
	c[len]=m%10;
	m=m/10;
	len++;
	}
	for(i=len-1;i>=1;i--) {cout<<c[i];}
}
int main(){
	long long N,a[100005],b[100005],j=1;
	memset(a,0,sizeof(a));
	memset(b,0,sizeof(b));
	cin>>N;
	for(int i=1;i<=N;i++)
		cin>>a[i];
	sort(a+1,a+N+1);
	for(int i=N;i>=1;i-=2){
		if(a[i]==a[i-1]){
			b[j]=a[i];
			j++;
		}
	}
	if(b[1]==0||b[2]==0){
		cout<<0<<endl;
		return 0;
	}
	chengfa(b[1],b[2]);
	return 0;
}


Compiler output:
a.cc:22:1: error: ISO C++ forbids declaration of 'chengfa' with no type [-fpermissive]
   22 | chengfa(int n,int m){
      | ^~~~~~~
a.cc: In function 'int chengfa(int, int)':
a.cc:57:1: warning: no return statement in function returning non-void [-Wreturn-type]
   57 | }
      | ^
Language: C++

#include <bits/stdc++.h>

#define ll long long
#define ld long double
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
//    string s;
//    cin >> s;
//    set<char> se;
//    for (auto i = s.begin(); i != s.end(); i++)
//        se.insert(*i);
//    for (char i = 'z'; i!= 'a'; i++){
//        if (se.find(i) == se.end()){
//            cout << i << endl;
//            return 0;
//        }
//    }
//    cout << "None" << endl;
    ll n;
    cin >> n;
    ll a[n+1];
    for (ll i = 1; i <= n; i++){
        cin >> a[i];
    }
    sort(a+1,a+n+1);
    reverse(a+1,a+n+1);
    ll answ = 0;
    ll kv = 0;
    ll co = 0;
    ll o = 0;
    ll p = 0;
    for (ll i = 2; i <= n; i++){
        if (a[i] != a[i-1]){
            if (co >= 4 && p != 1){
                kv = max(kv,a[i-1]*a[i-1]);
                p = 1;
                if (answ == 0 && o == 0){
                    answ = a[i-1];
                    o = 1;
                } else if (o == 1){
                    answ = answ*a[i-1];
                    o = 2;
                }
            } else if (co >= 2) {
                if (answ == 0 && o == 0){
                    answ = a[i-1];
                    o = 1;
                } else if (o == 1){
                    answ = answ*a[i-1];
                    o = 2;
                }
            }
            co = 1;
        } else {
            co++;
        }
    }
    //cout << answ << " " << o << endl;
    if (co >= 4 && p != 1){
        kv = max(kv,a[n]*a[n]);
        p = 1;
        if (answ == 0 && o == 0){
            answ = a[i-1];
            o = 1;
        } else if (o == 1){
            answ = answ*a[i-1];
            o = 2;
        }
    } else if (co >= 2) {
        if (answ == 0 &&  o == 0){
            answ = a[n];
            o = 1;
        } else if (o == 1){
            answ = answ*a[n];
            o = 2;
        }
    }
    if (o != 2){
        answ = 0;
    }
    cout << max(answ,kv) << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:66:22: error: 'i' was not declared in this scope
   66 |             answ = a[i-1];
      |                      ^
a.cc:69:27: error: 'i' was not declared in this scope
   69 |             answ = answ*a[i-1];
      |                           ^
Language: C++

#include <iostream>
#include <map>
#include <string>
#include <vector>

using namespace std;
using ll = long long;

void solve() {
    int n;
    cin >> n;
    long a[n], lf = 0, ls = 0;
    for(int i = 0; i < n; i++){
        cin >> a[i];
    }
    sort(a, a+n);
    reverse(a, a+n);
    for(int i = 0; i < n; i++){
        if(lf == 0 && a[i] == a[i+1]){
            lf = a[i];
            i++;
        } else if(lf != 0 && a[i] == a[i+1]){
            ls = a[i];
            break;
        }
    }
    cout << lf*ls << endl;
}

int main() {
    solve();
    return 0;
}

Compiler output:
a.cc: In function 'void solve()':
a.cc:16:5: error: 'sort' was not declared in this scope; did you mean 'short'?
   16 |     sort(a, a+n);
      |     ^~~~
      |     short
a.cc:17:5: error: 'reverse' was not declared in this scope
   17 |     reverse(a, a+n);
      |     ^~~~~~~
Language: C++

#include <iostream>
//#include <math.h>
#include <string>
//#include <time.h>
//#include <conio.h>
#include <algorithm>
using namespace std;

int main()
{
	int n;
	cin >> n;
	int *arr = new int[n];

	for (int i = 0; i < n; i++)
		scanf_s("%d", &arr[i]);
	sort(arr, arr + n);
	int a = 0, b = 0;
	for (int i = n - 1; i > 0;i--)
		if (arr[i] == arr[i - 1])
		{

			if (a == 0)
				a = arr[i];
			else b = arr[i];
			i--;
			if (a != 0 && b != 0)
				break;
		}
	long long ans = (long long)(a)*(long long)(b);
	cout << ans;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:17: error: 'scanf_s' was not declared in this scope; did you mean 'scanf'?
   16 |                 scanf_s("%d", &arr[i]);
      |                 ^~~~~~~
      |                 scanf
Language: C

#include<stdio.h>
#include<string>
#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<functional>

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

int a[10500];

int main()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> a[i];
	}
	sort(a, a + n,greater<int>());

	int ope = 0;
	int c=0, d=0;
	int i = 0;
	while(i < n-1 ) {
		if (a[i] == a[i + 1]) {
			if (ope == 0)c = a[i];
			else d = a[i];
			ope++;
			i += 2;
		}
		else i++;
		if (ope == 2)break;
	}
	cout << c*d << endl;

	return 0;
}


Compiler output:
main.c:2:9: fatal error: string: No such file or directory
    2 | #include<string>
      |         ^~~~~~~~
compilation terminated.
Language: C++

#include <map>

int A[1000000001];
int main() {
  int N;
  std::cin >> N;
  size_t max_a = 0;
  for (int i = 0; i < N; i++) {
    size_t a;
    std::cin >> a;
    A[a]++;
    if (max_a < a) {
      max_a = a;
    }
  }

  size_t max = 0;
  for (size_t i = max_a; i > 0; i--) {
    if (A[i] >= 2) {
      if (max == 0) {
        max = i;
      } else {
        std::cout << max * i << std::endl;
        return 0;
      }
    }
  }
  std::cout << 0 << std::endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:6:8: error: 'cin' is not a member of 'std'
    6 |   std::cin >> N;
      |        ^~~
a.cc:2:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    1 | #include <map>
  +++ |+#include <iostream>
    2 | 
a.cc:10:10: error: 'cin' is not a member of 'std'
   10 |     std::cin >> a;
      |          ^~~
a.cc:10:10: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:23:14: error: 'cout' is not a member of 'std'
   23 |         std::cout << max * i << std::endl;
      |              ^~~~
a.cc:23:14: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:23:38: error: 'endl' is not a member of 'std'
   23 |         std::cout << max * i << std::endl;
      |                                      ^~~~
a.cc:2:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    1 | #include <map>
  +++ |+#include <ostream>
    2 | 
a.cc:28:8: error: 'cout' is not a member of 'std'
   28 |   std::cout << 0 << std::endl;
      |        ^~~~
a.cc:28:8: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:28:26: error: 'endl' is not a member of 'std'
   28 |   std::cout << 0 << std::endl;
      |                          ^~~~
a.cc:28:26: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
Language: C++

#include <iostream>
//#include <math.h>
#include <string>
//#include <time.h>
//#include <conio.h>
#include <algorithm>
using namespace std;

int main()
{
	int n;
	cin >> n;
	int *arr = new int[n];

	for (int i = 0; i < n; i++)
		scanf_s("%d", &arr[i]);
	sort(arr, arr + n);
	int a = 0, b = 0;
	for (int i = n - 1; i > 0;i--)
		if (arr[i] == arr[i - 1])
		{

			if (a == 0)
				a = arr[i];
			else b = arr[i];
			i--;
			if (a != 0 && b != 0)
				break;
		}
	cout << a*b;

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:17: error: 'scanf_s' was not declared in this scope; did you mean 'scanf'?
   16 |                 scanf_s("%d", &arr[i]);
      |                 ^~~~~~~
      |                 scanf
Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0; i < (ll)(n); i++)
#define rep2(i, a, n) for(ll i = a; i < (ll)(n); i++)
#define memi cout << endl
#define kono(n) cout << fixed << setprecision(n)
#define all(c) (c).begin(), (c).end()
#define pb push_back
#define hina cout << ' '
#define in(n) cin >> n
#define in2(n, m) cin >> n >> m
#define in3(n, m, l) cin >> n >> m >> l
#define out(n) cout << n
const ll mei = (ll)1e9 + 7;

int main(){
  ll n, a, i;
  in(n);
  string s, t;
  in2(s, t);
  ll dp[n];
  if(s[0] == t[0]){
    a = 0;
    i = 1;
    dp[0] = 3;
  }
  else{
    a = 1;
    i = 2;
    dp[1] = 6;
  }
  while(i < n){
    if(a = 0){
      if(s[i] == t[i]){
        dp[i] = 2 * dp[i - 1];
        i++;
      }
      else{
        dp[i + 1] = 2 * dp[i - 1];
        a = 1;
        i += 2;
      }
    }
    else{
      if(s[i] == t[i]){
        dp[i] = d[i - 1];
        a = 0;
        i++;
      }
      else{
        dp[i + 1] = 3 * dp[i - 1];
        i += 2;
      }
    }
  }
  out(dp[n - 1]);
  memi;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:47:17: error: 'd' was not declared in this scope; did you mean 'dp'?
   47 |         dp[i] = d[i - 1];
      |                 ^
      |                 dp
Language: C++

#include<bits/stdc++.h>
#include<unordered_set>
#include<unordered_map>
#include <iostream>
#include <string>
#include <cmath>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i,a,b) for(ll i=(a);i<(b);i++)
#define FORR(i,a,b)for(ll i=(a);i<=(b);i++)
#define repR(i,n) for(ll i=n;i>=0;i--)
#define all(v)(v).begin(),(v).end()
#define rall(v)(v).rbegin(),(v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout<<(x)<<endl
#define PQ priority_queue<ll>
#define PQR priority_queue<ll,vector<ll>,greater<ll>>
#define YES(n) cout << ((n) ? "YES" : "NO"  ) << endl
#define Yes(n) cout << ((n) ? "Yes" : "No"  ) << endl
#define mp make_pair
#define maxs(x,y) (x = max(x,y))
#define mins(x,y) (x = min(x,y))
#define sz(x) (int)(x).size()
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using pll = pair<ll, ll>;
using vc = vector<char>;
using vvc = vector<vc>;
ll dx[4]={0,1,0,-1};
ll dy[4]={1,0,-1,0};
int main(){
  ll n;
  cin>>n;
  string s1,s2;
  cin>>s1>>s2;
  s1.pb('6');
  ll cu=0;
  rep(i,n){
    if(s1[i]!=s1[i+1]){
      if(i==0) ans*=3;
      else if(cu) {
        cu=0;
        continue;
      }
      else{
        ans*=2;
      ans%=MOD;
      }
    }
    else{
      if(i==0){
        ans*=6;
      }
      else{
        ans*=2;
        ans%=MOD;
      }
      i++;
      cu=1;
    }
  }
  COUT(ans);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:51:16: error: 'ans' was not declared in this scope; did you mean 'abs'?
   51 |       if(i==0) ans*=3;
      |                ^~~
      |                abs
a.cc:57:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   57 |         ans*=2;
      |         ^~~
      |         abs
a.cc:63:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   63 |         ans*=6;
      |         ^~~
      |         abs
a.cc:66:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   66 |         ans*=2;
      |         ^~~
      |         abs
a.cc:73:8: error: 'ans' was not declared in this scope; did you mean 'abs'?
   73 |   COUT(ans);
      |        ^~~
a.cc:19:24: note: in definition of macro 'COUT'
   19 | #define COUT(x) cout<<(x)<<endl
      |                        ^
Language: C++

#include<bits/stdc++.h>
#include<unordered_set>
#include<unordered_map>
#include <iostream>
#include <string>
#include <cmath>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i,a,b) for(ll i=(a);i<(b);i++)
#define FORR(i,a,b)for(ll i=(a);i<=(b);i++)
#define repR(i,n) for(ll i=n;i>=0;i--)
#define all(v)(v).begin(),(v).end()
#define rall(v)(v).rbegin(),(v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout<<(x)<<endl
#define PQ priority_queue<ll>
#define PQR priority_queue<ll,vector<ll>,greater<ll>>
#define YES(n) cout << ((n) ? "YES" : "NO"  ) << endl
#define Yes(n) cout << ((n) ? "Yes" : "No"  ) << endl
#define mp make_pair
#define maxs(x,y) (x = max(x,y))
#define mins(x,y) (x = min(x,y))
#define sz(x) (int)(x).size()
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using pll = pair<ll, ll>;
using vc = vector<char>;
using vvc = vector<vc>;
ll dx[4]={0,1,0,-1};
ll dy[4]={1,0,-1,0};
int main(){
  ll n;
  cin>>n;
  stirng s1,s2;
  cin>>s1>>s2;
  s1.pb('6');
  ll cu=0;
  rep(i,n){
    if(s1[i]!=s1[i+1]){
      if(i==0) ans*=3;
      else if(cu) {
        cu=0;
        continue;
      }
      else{
        ans*=2;
      ans%=MOD;
      }
    }
    else{
      if(i==0){
        ans*=6;
      }
      else{
        ans*=2;
        ans%=MOD;
      }
      i++;
      cu=1;
    }
  }
  COUT(ans);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:45:3: error: 'stirng' was not declared in this scope
   45 |   stirng s1,s2;
      |   ^~~~~~
a.cc:46:8: error: 's1' was not declared in this scope; did you mean 'y1'?
   46 |   cin>>s1>>s2;
      |        ^~
      |        y1
a.cc:46:12: error: 's2' was not declared in this scope; did you mean 'sz'?
   46 |   cin>>s1>>s2;
      |            ^~
      |            sz
a.cc:51:16: error: 'ans' was not declared in this scope; did you mean 'abs'?
   51 |       if(i==0) ans*=3;
      |                ^~~
      |                abs
a.cc:57:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   57 |         ans*=2;
      |         ^~~
      |         abs
a.cc:63:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   63 |         ans*=6;
      |         ^~~
      |         abs
a.cc:66:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   66 |         ans*=2;
      |         ^~~
      |         abs
a.cc:73:8: error: 'ans' was not declared in this scope; did you mean 'abs'?
   73 |   COUT(ans);
      |        ^~~
a.cc:19:24: note: in definition of macro 'COUT'
   19 | #define COUT(x) cout<<(x)<<endl
      |                        ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define REP(i, d, n) for(int i=(d); i<(n); ++i)
#define all(v) v.begin(), v.end()
using ll = long long;
using P = pair<int, int>;
const int mod = 1000000007;
struct mint {
    ll x; // typedef long long ll;
    mint(ll x=0) : x((x%mod+mod)%mod) {}
    mint operator-() const { 
      return mint(-x);
    }
    mint& operator+=(const mint a) {
        if ((x += a.x) >= mod) x -= mod;
        return *this;
    }
    mint& operator-=(const mint a) {
        if ((x += mod-a.x) >= mod) x -= mod;
        return *this;
    }
    mint& operator*=(const mint a) {
        (x *= a.x) %= mod;
        return *this;
    }
    mint operator+(const mint a) const {
        mint res(*this);
        return res+=a;
    }
    mint operator-(const mint a) const {
        mint res(*this);
        return res-=a;
    }
    mint operator*(const mint a) const {
        mint res(*this);
        return res*=a;
    }
    mint pow(ll t) const {
        if (!t) return 1;
        mint a = pow(t>>1);
        a *= a;
        if (t&1) a *= *this;
        return a;
    }

    // for prime mod
    mint inv() const {
        return pow(mod-2);
    }
    mint& operator/=(const mint a) {
        return (*this) *= a.inv();
    }
    mint operator/(const mint a) const {
        mint res(*this);
        return res/=a;
    }
};
int main() {

    int n;
    cin >> n;
    string s1, s2;
    cin >> s1 >> s2;    

    mint ans = 1;
    bool flag;
    if(s1[0] == s2[0]){
        ans *= 3;
        flag = true
    }
    else{
        ans *= 6;
        flag = false;
    }
    REP(i, 1, n){
        if(s1[i] == s2[i]){
            ans *= 2;
            flag = true;
        }
        else{
            i++;
            if(!flag){
                ans *= 3;
            }
            flag = false;
        }
    }
    cout << ans.x << endl;

    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:70:20: error: expected ';' before '}' token
   70 |         flag = true
      |                    ^
      |                    ;
   71 |     }
      |     ~
Language: C++

#include <bits/stdc++.h>

using ll = long long;

#define mod 1000000007
#define REP(i, n) for (int i = 0; i < n; i++)

using namespace std;

//long C(long n, long r);
//long long gcd(long long a, long long b);
//long long lcm(long long a, long long b);
 

void solve() {
    int N;
    cin >> N;
    string s1, s2;
    cin >> s1 >> s2;
    int i = 0;
    ll ans = 1;
    bool prev;
    if(s1[i] == s2[i]){
        ans *= 3ll;
        prev = true;
        i++;
    }
    else{
        ans *= 6ll;
        prev = false;
        i += 2;
    }

    for(i;i < N; i++){
        if(s1[i] == s2[i]){
            if(prev) {
                ans = (ans * 2ll) % mod;
            }
            else{
                ans = (ans * 1ll) % mod;
            }
            prev = true;
        }
        else{
            if(prev) {
                ans = (ans * 2ll) % mod;
            }
            else{
                ans = (ans * 3ll) % mod;
            }
            prev = false;
            i++;
        }
    }
    cout << ans << endl;
}

Compiler output:
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/14/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x17): undefined reference to `main'
collect2: error: ld returned 1 exit status
Language: C++

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


int main()
{
  int n;
  cin>>n;
  string s1,s2;
  
  cin>>s1>>s2;
  long ans=0;
  bool currpos,lastpos;
  int i==;
  if(s1[0]==s2[0])
  {
    ans=3;
    currpos=0;     //position=0 means vertical
	i=1;  
  }
  else{
    ans=6;
    currpos=1;
    i=2;
  }
  lastpos=currpos;
  while(i<n)
  {
	 if(lastpos==0)
     {
       ans=ans*2;
       if(s1[i]==s2[i])
       {
         i=i+1;
         currpos=0;
       }
       else{ i=i+2;
            currpos=1;}
       
     }
     else
     {
       if(s1[i]!=s2[i])
       {
         ans=ans*3;
         i=i+2;
         currpos=1;
         
       }
       else
       {
         i++;
         currpos=0;
       }
       
     }
    
    
    lastpos=currpos;
  }
  
  cout<<ans<<endl;
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:8: error: expected initializer before '==' token
   14 |   int i==;
      |        ^~
a.cc:19:9: error: 'i' was not declared in this scope
   19 |         i=1;
      |         ^
a.cc:24:5: error: 'i' was not declared in this scope
   24 |     i=2;
      |     ^
a.cc:27:9: error: 'i' was not declared in this scope
   27 |   while(i<n)
      |         ^