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

#include<bits/stdc++.h>
int main(void){
useing namespace std
  int a,b,s;
  cin >> a,b ;

	s = (a+b)/2;

if(fabs(a-s) == fabs(b-s)){
  cout<< s <<emdl;
  else{
    cout<< "impossible"<<endl;
  }
}
  return 0;
}
  

　　
    



Compiler output:
a.cc:19:1: error: extended character 　 is not valid in an identifier
   19 | 　　
      | ^
a.cc:19:1: error: extended character 　 is not valid in an identifier
a.cc: In function 'int main()':
a.cc:3:1: error: 'useing' was not declared in this scope
    3 | useing namespace std
      | ^~~~~~
a.cc:5:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |   cin >> a,b ;
      |   ^~~
      |   std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:5:10: error: 'a' was not declared in this scope
    5 |   cin >> a,b ;
      |          ^
a.cc:5:12: error: 'b' was not declared in this scope
    5 |   cin >> a,b ;
      |            ^
a.cc:7:9: error: 's' was not declared in this scope
    7 |         s = (a+b)/2;
      |         ^
a.cc:10:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |   cout<< s <<emdl;
      |   ^~~~
      |   std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:10:14: error: 'emdl' was not declared in this scope
   10 |   cout<< s <<emdl;
      |              ^~~~
a.cc:11:3: error: expected '}' before 'else'
   11 |   else{
      |   ^~~~
a.cc:9:27: note: to match this '{'
    9 | if(fabs(a-s) == fabs(b-s)){
      |                           ^
a.cc:12:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   12 |     cout<< "impossible"<<endl;
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:12:26: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   12 |     cout<< "impossible"<<endl;
      |                          ^~~~
      |                          std::endl
In file included from /usr/include/c++/14/istream:41,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc: At global scope:
a.cc:15:3: error: expected unqualified-id before 'return'
   15 |   return 0;
      |   ^~~~~~
a.cc:16:1: error: expected declaration before '}' token
   16 | }
      | ^
a.cc:19:1: error: '\U00003000\U00003000' does not name a type
   19 | 　　
      | ^~~~
Language: C++

#include<bits/stdc++>
int main(void){
useing namespace std
  int a,b,s;
  cin >> a,b ;

	s = (a+b)/2;

if(fabs(a-s) == fabs(b-s)){
  cout<< s <<emdl;
  else{
    cout<< "impossible"<<endl;
  }
}
  return 0;
}
  

　　
    



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

#include<iostream>
using namespace std;
int main(){
  int a,b;
  cin>>a>>b;
  cout<<(a+b)%2?"IMPOSSIBLE":(a+b)/2;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:16: error: operands to '?:' have different types 'const char*' and 'int'
    6 |   cout<<(a+b)%2?"IMPOSSIBLE":(a+b)/2;
      |   ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
Language: C++

a, b = gets.split.map(&:to_i)
if (a + b) % 2 == 1
  puts "IMPOSSIBLE"
else
  puts (a + b) / 2
end

Compiler output:
a.cc:1:1: error: 'a' does not name a type
    1 | a, b = gets.split.map(&:to_i)
      | ^
Language: Java

int x = A + B;
if(x%2!=0){
  System.out.println("IMPOSSIBLE");
}else{
  System.out.println(x%2);
}


Compiler output:
Main.java:1: error: unnamed classes are a preview feature and are disabled by default.
int x = A + B;
^
  (use --enable-preview to enable unnamed classes)
Main.java:2: error: class, interface, enum, or record expected
if(x%2!=0){
^
Main.java:4: error: class, interface, enum, or record expected
}else{
^
Main.java:6: error: class, interface, enum, or record expected
}
^
4 errors
Language: C++

#include <iostream>

int main(){
	int a[50]={}, b[50]={}, n, i=0;
	std::cin >> n;
	for(i;i<n; i++) std::cin >> a[i];
	for(i; i<n; i++) std::cin >> b[i];
	int f[50][50]={{}};
	f[0][0] = min(a[0], b[0]);
	f[0][1] = min(a[1], b[0] - f[0][0]);
	for(i=1; i<n; i++){
		f[i][i+1] = min(a[i+1], b[i] - f[i][i]);
		f[i][i] = min(a[i] - f[i-1][i], b[i]);
	}
	for(i; i<n; i++){
		int num =0;
		num += f[i][i] + f[i][i+1];
	}
	std::cout << num;
	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:19: error: 'min' was not declared in this scope; did you mean 'std::min'?
    9 |         f[0][0] = min(a[0], b[0]);
      |                   ^~~
      |                   std::min
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:281:5: note: 'std::min' declared here
  281 |     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
a.cc:19:22: error: 'num' was not declared in this scope; did you mean 'enum'?
   19 |         std::cout << num;
      |                      ^~~
      |                      enum
Language: C++

#include <stdio.h>
#include <string.h>
#include<conio.h>
//#include<iostream.h>
int main(){
long	long int n,t,i,len,j,l;
	
	scanf("%lld",&t);

		scanf("%lld",&n);
		l=t+n;
		if(l%2==0)
		printf("%lld\n",l/2);
		else
		printf("Impossible\n");
	
	}

Compiler output:
a.cc:3:9: fatal error: conio.h: No such file or directory
    3 | #include<conio.h>
      |         ^~~~~~~~~
compilation terminated.
Language: C++

/* package whatever; // don't place package name! */

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

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		int a = Integer.parseInt(args[0]);
		int b = Integer.parseInt(args[1]);

		if ((a + b)%2 == 0) {
			System.out.println((a + b)%2);
		} else {
			System.out.println("IMPOSSIBLE");
		}
	}
}

Compiler output:
a.cc:3:1: error: 'import' does not name a type
    3 | import java.util.*;
      | ^~~~~~
a.cc:3:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:4:1: error: 'import' does not name a type
    4 | import java.lang.*;
      | ^~~~~~
a.cc:4:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:5:1: error: 'import' does not name a type
    5 | import java.io.*;
      | ^~~~~~
a.cc:5:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:10:15: error: expected ':' before 'static'
   10 |         public static void main (String[] args) throws java.lang.Exception
      |               ^~~~~~~
      |               :
a.cc:10:34: error: 'String' has not been declared
   10 |         public static void main (String[] args) throws java.lang.Exception
      |                                  ^~~~~~
a.cc:10:43: error: expected ',' or '...' before 'args'
   10 |         public static void main (String[] args) throws java.lang.Exception
      |                                           ^~~~
a.cc:10:47: error: expected ';' at end of member declaration
   10 |         public static void main (String[] args) throws java.lang.Exception
      |                                               ^
      |                                                ;
a.cc:10:49: error: 'throws' does not name a type
   10 |         public static void main (String[] args) throws java.lang.Exception
      |                                                 ^~~~~~
a.cc:21:2: error: expected ';' after class definition
   21 | }
      |  ^
      |  ;
Language: Java

class Main(){
  public static void main(String[] args){

Scanner scanner = new Scanner(System.in);
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		if ((A+B)%2==0) {
			System.out.println((A+B)/2);
		}else {
			System.out.println("IMPOSSIBLE");
		}
}
}

Compiler output:
Main.java:1: error: '{' expected
class Main(){
          ^
1 error
Language: Java

package coding;
import java.util.Scanner;
 
public class Coding {
  
  public static void main(String[] args)  {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int A[] = new int[n+1];
    int B[] = new int[n];
    
    int tVil = 0;
    for(int i = 0; i <= n; i++) {
      A[i] = sc.nextInt();
      tVil += A[i];
    }
    for(int i = 0; i < n; i++) {
      B[i] = sc.nextInt();
    }
    
    /*for(int i = 0; i < n; i++) {
      tVil = tVil - A[i];
      int remPower = B[i]-A[i];
      A[i+1] = A[i+1] - remPower;
      if(A[i+1] < 0) A[i+1] = 0;
      else {
        tVil = tVil - remPower;
      }
    }
    System.out.println(tVil);*/
    
  }
}

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

import java.util.Scanner;
 
public class Main {
  
  public static void main()  {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int A[] = new int[n+1];
    int B[] = new int[n];
    
    int tVil = 0;
    for(int i = 0; i <= n; i++) {
      A[i] = sc.nextInt();
      tVil += A[i];
    }
    for(int i = 0; i < n; i++) {
      B[i] = sc.nextInt();
    }
    
    for(int i = 0; i < n; i++) {
      tVil = tVil - A[i];
      int remPower = B[i]-A[i];
      A[i+1] = A[i+1] - remPower;
      if(A[i+1] < 0) A[i+1] = 0;
      else {
        tVil = tVil - rem;
      }
    }
    System.out.println(tVil);
    
  }
}

Compiler output:
Main.java:26: error: cannot find symbol
        tVil = tVil - rem;
                      ^
  symbol:   variable rem
  location: class Main
1 error
Language: Java

import java.util.Scanner;

public class Main {
  
  public static void main()  {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int A[] = new int[n+1];
    int B[] = new int[n];
    
    int tVil = 0;
    for(int i = 0; i <= n; i++) {
      A[i] = sc.nextInt();
      tVil += A[i];
    }
    for(int i = 0; i < n; i++) {
      B[i] = sc.nextInt();
    }
    
    for(int i = 0; i < n; i++) {
      tVil = tVil - A[i];
      int remPower = B[i]-A[i];
      A[i+1] = A[i+1] - remPower;
      if(A[i+1] < 0) A[i+1] = 0;
      else {
        tVil = tVil - rem;
      }
    }
    System.out.println(tVil);
    
  }
}

Compiler output:
Main.java:26: error: cannot find symbol
        tVil = tVil - rem;
                      ^
  symbol:   variable rem
  location: class Main
1 error
Language: Java

public class Main {
  
  public static void main()  {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int A[] = new int[n+1];
    int B[] = new int[n];
    
    int tVil = 0;
    for(int i = 0; i <= n; i++) {
      A[i] = sc.nextInt();
      tvil+=A[i];
    }
    for(int i = 0; i < n; i++) {
      B[i] = sc.nextInt();
    }
    
    for(int i = 0; i < n; i++) {
      tVil = tVil - A[i];
      int remPower = B[i]-A[i];
      A[i+1] = A[i+1] - remPower;
      if(A[i+1] < 0) A[i+1] = 0;
      else {
        tVil = tVil - rem;
      }
    }
    System.out.println(tVil);
    
  }
}

Compiler output:
Main.java:4: error: cannot find symbol
    Scanner sc = new Scanner(System.in);
    ^
  symbol:   class Scanner
  location: class Main
Main.java:4: error: cannot find symbol
    Scanner sc = new Scanner(System.in);
                     ^
  symbol:   class Scanner
  location: class Main
Main.java:12: error: cannot find symbol
      tvil+=A[i];
      ^
  symbol:   variable tvil
  location: class Main
Main.java:24: error: cannot find symbol
        tVil = tVil - rem;
                      ^
  symbol:   variable rem
  location: class Main
4 errors
Language: Java

public class Main {
  
  public static void main()  {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int A[] = new int[n+1];
    int B[n] = new int[n];
    
    int tVil = 0;
    for(int i = 0; i <= n; i++) {
      A[i] = sc.nextInt();
      tvil+=A[i];
    }
    for(int i = 0; i < n; i++) {
      B[i] = sc.nextInt();
    }
    
    for(int i = 0; i < n; i++) {
      tVil = tVil - A[i];
      int remPower = B[i]-A[i];
      A[i+1] = A[i+1] - remPower;
      if(A[i+1] < 0) A[i+1] = 0;
      else {
        tVil = tVil - rem;
      }
    }
    System.out.println(tVil);
    
  }
}

Compiler output:
Main.java:7: error: ']' expected
    int B[n] = new int[n];
          ^
Main.java:7: error: ';' expected
    int B[n] = new int[n];
           ^
Main.java:7: error: not a statement
    int B[n] = new int[n];
               ^
3 errors
Language: C++

#include<bits/stdc++.h>

using namespace std;

#define maxn 1005
#define ll long long
typedef pair<int,int> PII;
const int mod = 1e9+7;

ll a,b;

int main()
{
    init();
    cin>>a>>b;
    if((a+b)%2==0)cout<<(a+b)/2;
    else cout<<"IMPOSSIBLE";
}


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

#![allow(dead_code)]
use std::io::*;

fn main(){
    let a: i32 = read();
    let b: i32 = read();
    if (a + b) % 2 == 0 {
        println!("{}", (a + b) / 2)
    }else{
        println!("IMPOSSIBLE");
    }
    
}

fn upper_bound(a: &Vec<i32>, x: &i32) -> Option<usize>
{
    let mut ok: isize = a.len() as isize;
    let mut ng: isize = -1;
    if ok == 0 || a[ok as usize - 1] <= *x{
        None
    }else{
        while (ng - ok).abs() > 1{
            let mid = (ok + ng) / 2;
            if a[mid as usize] > *x{
                ok = mid;
            }else{
                ng = mid;
            }
        }
        Some(ok as usize)
    }
}

fn read<T>() -> T
where
    T: std::str::FromStr,
{
    let stdin = std::io::stdin();
    let token: String = stdin
        .lock()
        .bytes()
        .map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().unwrap()
}


Compiler output:
a.cc:1:2: error: invalid preprocessing directive #!
    1 | #![allow(dead_code)]
      |  ^
a.cc:2:1: error: 'use' does not name a type
    2 | use std::io::*;
      | ^~~
a.cc:4:1: error: 'fn' does not name a type
    4 | fn main(){
      | ^~
a.cc:15:1: error: 'fn' does not name a type
   15 | fn upper_bound(a: &Vec<i32>, x: &i32) -> Option<usize>
      | ^~
a.cc:34:1: error: 'fn' does not name a type
   34 | fn read<T>() -> T
      | ^~
Language: Java

import java.util.concurrent.atomic.AtomicBoolean;
import java.util.stream.IntStream;

public class Hoge
{
    public static void main(String[] args) {
        int a = Integer.parseInt(args[0]);
        int b = Integer.parseInt(args[1]);
        int k = 0;
        for (k=0; k<1000000000; k++) {
            int absA = Math.abs(a - k);
            int absB = Math.abs(b - k);
            if (absA == absB) {
                System.out.println(k);
                break;
            } 
        }
        if (k == 0) {
            System.out.println("IMPOSSIBLE");
        }
    }
}


Compiler output:
Main.java:4: error: class Hoge is public, should be declared in a file named Hoge.java
public class Hoge
       ^
1 error
Language: Java

import java.util.concurrent.atomic.AtomicBoolean;
import java.util.stream.IntStream;

public class Test
{
    public static void main(int[] args) {
        int a = args[0];
        int b = args[1];
        AtomicBoolean ab = new AtomicBoolean(false);
        IntStream.range(0, (int)Math.pow(10, 9)).forEach(k -> {
            int absA = Math.abs(a - k);
            int absB = Math.abs(b - k);
            if (absA == absB) {
                ab.set(true);
                System.out.println(k);
                return;
            } 
        });
        if (!ab.get()) {
            System.out.println("IMPOSSIBLE");
        }
    }
}


Compiler output:
Main.java:4: error: class Test is public, should be declared in a file named Test.java
public class Test
       ^
1 error
Language: Java

        int a = Integer.parseInt(args[0]);
        int b = Integer.parseInt(args[1]);
        AtomicBoolean ab = new AtomicBoolean(false);
        IntStream.range(0, (int)Math.pow(10, 9)).forEach(k -> {
            int absA = Math.abs(a - k);
            int absB = Math.abs(b - k);
            if (absA == absB) {
                ab.set(true);
                System.out.println(k);
                return;
            } 
        });
        if (!ab.get()) {
            System.out.println("IMPOSSIBLE");
        }


Compiler output:
Main.java:1: error: unnamed classes are a preview feature and are disabled by default.
        int a = Integer.parseInt(args[0]);
        ^
  (use --enable-preview to enable unnamed classes)
Main.java:4: error: class, interface, enum, or record expected
        IntStream.range(0, (int)Math.pow(10, 9)).forEach(k -> {
        ^
Main.java:7: error: class, interface, enum, or record expected
            if (absA == absB) {
            ^
Main.java:9: error: class, interface, enum, or record expected
                System.out.println(k);
                ^
Main.java:10: error: class, interface, enum, or record expected
                return;
                ^
Main.java:11: error: class, interface, enum, or record expected
            } 
            ^
Main.java:13: error: class, interface, enum, or record expected
        if (!ab.get()) {
        ^
Main.java:15: error: class, interface, enum, or record expected
        }
        ^
8 errors
Language: C++

#include<iostream>
#include<cmath>
using namespace std;
int main(){
  int A,B;
  cin>>A>>B;
  for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:33: error: 'a' was not declared in this scope
    7 |   for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
      |                                 ^
a.cc:7:43: error: 'b' was not declared in this scope
    7 |   for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
      |                                           ^
Language: C++

#include<iostream>
#include<cmath>
int main(){
  int A,B;
  cin>>A>>B;
  for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |   cin>>A>>B;
      |   ^~~
      |   std::cin
In file included from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:6:33: error: 'a' was not declared in this scope
    6 |   for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
      |                                 ^
a.cc:6:43: error: 'b' was not declared in this scope
    6 |   for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
      |                                           ^
a.cc:6:50: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    6 |   for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
      |                                                  ^~~~
      |                                                  std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:6:59: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    6 |   for(int i=A;i<=B;++i) if( abs(a-i)==abs(b-i) ) cout<<i<<endl;
      |                                                           ^~~~
      |                                                           std::endl
In file included from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
Language: C++

#include <bits/tsdc++.h>
using namespace std;
int main(){
  long long a,b;
  cin >> a >> b;
  if((a-b) % 2 == 1)cout << "IMPOSSIBLE" << endl;
  else{
    cout << (a+b)/2 << endl;
  }
}

Compiler output:
a.cc:1:10: fatal error: bits/tsdc++.h: No such file or directory
    1 | #include <bits/tsdc++.h>
      |          ^~~~~~~~~~~~~~~
compilation terminated.
Language: C

#include <stdio.h>
#include <stdlib.h>
int main() 
{
  int c;
  long long int a,b;
  scanf("%lld %lld",&a,&b);
  if((a%2==0) && (b%2==0))
  {
  c=abs((a+b)/2);
  printf("%d",c);
  }
  else if((a%2!==0) && (b%2!==0))
  {
  c=abs((a+b)/2);
  printf("%d",c);
  }
  else
  printf("Impossible\n");
  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:13:17: error: expected expression before '=' token
   13 |   else if((a%2!==0) && (b%2!==0))
      |                 ^
Language: C++

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Xinyi Tao
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        AHarmonyABC135 solver = new AHarmonyABC135();
        solver.solve(1, in, out);
        out.close();
    }

    static class AHarmonyABC135 {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int a = in.nextInt();
            int b = in.nextInt();
            if (a == b) out.println(0);
            else if ((a + b) % 2 == 1) out.println("IMPOSSIBLE");
            else out.println((a + b) / 2);
        }

    }
}



Compiler output:
a.cc:1:1: error: 'import' does not name a type
    1 | import java.io.OutputStream;
      | ^~~~~~
a.cc:1:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:2:1: error: 'import' does not name a type
    2 | import java.io.IOException;
      | ^~~~~~
a.cc:2:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:3:1: error: 'import' does not name a type
    3 | import java.io.InputStream;
      | ^~~~~~
a.cc:3:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:4:1: error: 'import' does not name a type
    4 | import java.io.PrintWriter;
      | ^~~~~~
a.cc:4:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:5:1: error: 'import' does not name a type
    5 | import java.util.Scanner;
      | ^~~~~~
a.cc:5:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:13:1: error: expected unqualified-id before 'public'
   13 | public class Main {
      | ^~~~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
	long long a,b,k;
  	cin>>a>>b;
  	k=(a+b)/2;
  	if(abs(a-k)=abs(b-k))cout<<k;
  	else cout<<"IMPOSSIBLE";
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:15: error: lvalue required as left operand of assignment
    7 |         if(abs(a-k)=abs(b-k))cout<<k;
      |            ~~~^~~~~
Language: C++

#include <bits/stdc++.h>
#define int long long
#define ld long double
#define endl '\n'
const int mod=1e9+9;
#define F first
#define S second
#define pb push_back
#define all(x) x.begin(),x.end()
#define si(a) a.size()
#define pii pair<int,int>
using namespace std;
#if !defined(ONLINE_JUDGE)
#include "debugging.h"
#endif
void fail(){cout<<"IMPOSSIBLE\n";exit(0);}

int32_t main() {
   std::ios::sync_with_stdio(false);cin.tie(NULL);
   int a,b;
   cin>>a>>b;
   if(a<b)swap(a,b);
   if(a%2 != b%2)fail();
   cout<<(a+b)/2<<endl;
   return 0;
}


Compiler output:
a.cc:14:10: fatal error: debugging.h: No such file or directory
   14 | #include "debugging.h"
      |          ^~~~~~~~~~~~~
compilation terminated.
Language: C++

# a - harmony

a , b = map(int,input().split())
if (a - b) % 2 == 0:
    print(a - (a - b)//2)
else:
    print("IMPOSSIBLE")

Compiler output:
a.cc:1:3: error: invalid preprocessing directive #a
    1 | # a - harmony
      |   ^
a.cc:3:1: error: 'a' does not name a type
    3 | a , b = map(int,input().split())
      | ^
Language: C++

#include <stdio.h>
using namespace std;

int main(){
  int a,b;
  cin>>a>>b;
  if((a+b)%2==0) cout<<(a+b)/2<<endl;
  else cout<<"IMPOSSIBLE"<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:3: error: 'cin' was not declared in this scope
    6 |   cin>>a>>b;
      |   ^~~
a.cc:2:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    1 | #include <stdio.h>
  +++ |+#include <iostream>
    2 | using namespace std;
a.cc:7:18: error: 'cout' was not declared in this scope
    7 |   if((a+b)%2==0) cout<<(a+b)/2<<endl;
      |                  ^~~~
a.cc:7:18: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:7:33: error: 'endl' was not declared in this scope
    7 |   if((a+b)%2==0) cout<<(a+b)/2<<endl;
      |                                 ^~~~
a.cc:2:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    1 | #include <stdio.h>
  +++ |+#include <ostream>
    2 | using namespace std;
a.cc:8:8: error: 'cout' was not declared in this scope
    8 |   else cout<<"IMPOSSIBLE"<<endl;
      |        ^~~~
a.cc:8:8: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:8:28: error: 'endl' was not declared in this scope
    8 |   else cout<<"IMPOSSIBLE"<<endl;
      |                            ^~~~
a.cc:8:28: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
Language: C++

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

int main(){
  int A, B;
  cin >> A >> B;
  if( (A+B)%2==0 ) cout << (A+B)/2;
  else cout << "IMPOSSIBLE";
}


Compiler output:
a.cc:1:2: error: invalid preprocessing directive #includes; did you mean #include?
    1 | #includes<bits/stdc++.h>
      |  ^~~~~~~~
      |  include
a.cc: In function 'int main()':
a.cc:6:3: error: 'cin' was not declared in this scope
    6 |   cin >> A >> B;
      |   ^~~
a.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | #includes<bits/stdc++.h>
a.cc:7:20: error: 'cout' was not declared in this scope
    7 |   if( (A+B)%2==0 ) cout << (A+B)/2;
      |                    ^~~~
a.cc:7:20: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:8:8: error: 'cout' was not declared in this scope
    8 |   else cout << "IMPOSSIBLE";
      |        ^~~~
a.cc:8:8: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
Language: C++

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

int main(){
  int A, B;
  cin >> A >> B;
  if( A+B%2==0 ) cout << (A+B)/2;
  else cout << "IMPOSSIBLE";
}


Compiler output:
a.cc:1:2: error: invalid preprocessing directive #includes; did you mean #include?
    1 | #includes<bits/stdc++.h>
      |  ^~~~~~~~
      |  include
a.cc: In function 'int main()':
a.cc:6:3: error: 'cin' was not declared in this scope
    6 |   cin >> A >> B;
      |   ^~~
a.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | #includes<bits/stdc++.h>
a.cc:7:18: error: 'cout' was not declared in this scope
    7 |   if( A+B%2==0 ) cout << (A+B)/2;
      |                  ^~~~
a.cc:7:18: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:8:8: error: 'cout' was not declared in this scope
    8 |   else cout << "IMPOSSIBLE";
      |        ^~~~
a.cc:8:8: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
Language: C++

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

int main(){
  int A, B;
  cin >> A >> B;
  if( A+B%2==0 ) cout << A+B/2;
  else cout << "IMPOSSIBLE";
}

Compiler output:
a.cc:1:2: error: invalid preprocessing directive #includes; did you mean #include?
    1 | #includes<bits/stdc++.h>
      |  ^~~~~~~~
      |  include
a.cc: In function 'int main()':
a.cc:6:3: error: 'cin' was not declared in this scope
    6 |   cin >> A >> B;
      |   ^~~
a.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | #includes<bits/stdc++.h>
a.cc:7:18: error: 'cout' was not declared in this scope
    7 |   if( A+B%2==0 ) cout << A+B/2;
      |                  ^~~~
a.cc:7:18: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:8:8: error: 'cout' was not declared in this scope
    8 |   else cout << "IMPOSSIBLE";
      |        ^~~~
a.cc:8:8: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
Language: Java

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

public class D {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int mod = (int)1e9 + 7;
        String v = scan.next();
        int[] dp = new int[13];
        int[] nx = new int[13];

        dp[0]= 1;
//        String v = reverseS(s);
        for (int i = 0; i < v.length(); i++) {
            Arrays.fill(nx,0);
            for (int j = 0; j < 13; j++) {
                for (int k = 0; k < 10; k++) {
                    if(k == v.charAt(i)-'0' || v.charAt(i) == '?') {
                        nx[(j * 10 + k) % 13] = (nx[(j * 10 + k) % 13] + dp[j])%mod;
                    }
                }
            }

            for (int j = 0; j < 13; j++) {
                dp[j] = nx[j];
            }
        }

        System.out.println(dp[5]);

    }

    private static String reverseS(String v) {
        String rs = "";
        for (int i = v.length()-1; i >=0; i--) {
            rs+=v.charAt(i);
        }
        return rs;
    }
}


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

#include <iostream>
#include <algorithm>
using namespace std;
int main(){
  int a,b;
  cin >> a >> b;
  if(abs(b-a)%2==0) cout << (a*a-b*b)/(2a-2b) << endl;
  else cout << "IMPOSSIBLE" << endl;
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:40: error: unable to find numeric literal operator 'operator""a'
    7 |   if(abs(b-a)%2==0) cout << (a*a-b*b)/(2a-2b) << endl;
      |                                        ^~
a.cc:7:43: error: unable to find numeric literal operator 'operator""b'
    7 |   if(abs(b-a)%2==0) cout << (a*a-b*b)/(2a-2b) << endl;
      |                                           ^~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
{
	long long a,b;
	cin>>a>>b;
	if(a%2!=b%2)
		cout<<"Impossible"<<endl;
	else
		cout<<"a+b"/2<<endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:28: error: invalid operands of types 'const char [4]' and 'int' to binary 'operator/'
   10 |                 cout<<"a+b"/2<<endl;
      |                       ~~~~~^~
      |                       |     |
      |                       |     int
      |                       const char [4]
Language: C++

#include<stdio.h>
int main(){
  int a,b,c;
  scanf("%d%d",&a,&b);
  c=(a+b)/2;
  if(c!==a||1==c%2){
    printf("%d", c);
    }
  else{
    printf("IMPOSSIBLE");
    }
  return 0;
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:6:9: error: expected primary-expression before '=' token
    6 |   if(c!==a||1==c%2){
      |         ^
Language: C++

#include<stdio.h>
int main(){
  int a,b,c;
  scanf("%d%d",&a,&b);
  c=(a+b)/2;
  if(c!==a||1==c%1){
    printf("%d", c);
    }
  else{
    printf("IMPOSSIBLE");
    }
  return 0;
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:6:9: error: expected primary-expression before '=' token
    6 |   if(c!==a||1==c%1){
      |         ^
Language: C++

A, B = map(int, input().split())
if (A + B) % 2 != 0:
    print('IMPOSSIBLE')
else:
    print((A + B) // 2)

Compiler output:
a.cc:3:11: warning: multi-character literal with 10 characters exceeds 'int' size of 4 bytes
    3 |     print('IMPOSSIBLE')
      |           ^~~~~~~~~~~~
a.cc:1:1: error: 'A' does not name a type
    1 | A, B = map(int, input().split())
      | ^
Language: C++

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

int main(){
    int A,B,C;
    cin >> A >> B;
    C = A + B / 2;
    if(|A-C|==|B-C|){
        cout << C << endl;
    }
    else{
        cout <<"IMPOSSIBLE"<<endl;
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:8: error: expected primary-expression before '|' token
    8 |     if(|A-C|==|B-C|){
      |        ^
a.cc:8:14: error: expected primary-expression before '=' token
    8 |     if(|A-C|==|B-C|){
      |              ^
a.cc:8:15: error: expected primary-expression before '|' token
    8 |     if(|A-C|==|B-C|){
      |               ^
a.cc:8:20: error: expected primary-expression before ')' token
    8 |     if(|A-C|==|B-C|){
      |                    ^
Language: C++

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

int main(){
    int A,B,C;
    cin >> A >> B;
  	if(A<0){
    A = -1 * A;
      if(B<0){
        B = -1 * B;
    }
    C = A + B / 2;
    if(A+B==C){
        cout << C << endl;
    }
    else{
        cout <<"IMPOSSIBLE"<<endl;
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:19:2: error: expected '}' at end of input
   19 | }
      |  ^
a.cc:4:11: note: to match this '{'
    4 | int main(){
      |           ^
Language: C

#include <stdio.h>
#include <math.h>

int main() {
	int A, B;
	double K;

	//AとBを読み込む
	scanf_s("%d %d", &A, &B);

	//Kの値の計算
	K = (A + B) / 2.0;

	(ceil(K) != floor(K)) ? printf("IMPOSSIBLE\n") : printf("%d\n", (int) K);
}

Compiler output:
main.c: In function 'main':
main.c:9:9: error: implicit declaration of function 'scanf_s'; did you mean 'scanf'? [-Wimplicit-function-declaration]
    9 |         scanf_s("%d %d", &A, &B);
      |         ^~~~~~~
      |         scanf
Language: C++

#include <iostream>
using namespace std;

int main() {
  int A, B;
  cin >> A >> B;
  if (A > B) {
    int tmp = A;
    A = B; B = tmp;
  }
  int C = B - A;
  if (C % 2 == 1) {
    cout << IMPOSSIBLE << endl;
  	return -1;
  }
  
  cout << A + C / 2 << endl;
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:13: error: 'IMPOSSIBLE' was not declared in this scope
   13 |     cout << IMPOSSIBLE << endl;
      |             ^~~~~~~~~~
Language: C++

int main() {
  int A, B;
  cin >> A >> B >> endl;
  if (A > B) {
    int tmp = A;
    A = B; B = tmp;
  }
  int C = B - A;
  if (C % 2 == 1) {
    cout << IMPOSSIBLE << endl;
  	return -1;
  }
  
  cout << A + C / 2 << endl;
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:3:3: error: 'cin' was not declared in this scope
    3 |   cin >> A >> B >> endl;
      |   ^~~
a.cc:3:20: error: 'endl' was not declared in this scope
    3 |   cin >> A >> B >> endl;
      |                    ^~~~
a.cc:10:5: error: 'cout' was not declared in this scope
   10 |     cout << IMPOSSIBLE << endl;
      |     ^~~~
a.cc:10:13: error: 'IMPOSSIBLE' was not declared in this scope
   10 |     cout << IMPOSSIBLE << endl;
      |             ^~~~~~~~~~
a.cc:14:3: error: 'cout' was not declared in this scope
   14 |   cout << A + C / 2 << endl;
      |   ^~~~
Language: C++

//JSD
#include<iostream>
#include<cmath>
using namespace std;
int main(){
  int n,m;
  if(abs(n-m)%2==0){
    cout<<abs(n-m)/2+min(n,m);
  else 
    cout<<"IMPOSSIBLE";
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:3: error: expected '}' before 'else'
    9 |   else
      |   ^~~~
a.cc:7:20: note: to match this '{'
    7 |   if(abs(n-m)%2==0){
      |                    ^
Language: C++

N = list(map(int, input().split()))
A = max(N) - min(N)

answer = 0
if A/2 == abs(int(A/2)):
  answer = A/2 + min(N)
else:
  answer = "IMPOSSIBLE"
  
print(answer)

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

#include <bits/stdc++.h>

using namespace std;

int main()
{
    ll a ,b;
    cin >> a >> b;
    ll mid = (a+b) / 2;
    ll ans1 = abs(a-mid);
    ll ans2 = abs(b-mid);
    if(ans1 == ans2) cout << mid << endl;
    else cout << "IMPOSSIBLE\n";
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:5: error: 'll' was not declared in this scope
    7 |     ll a ,b;
      |     ^~
a.cc:8:12: error: 'a' was not declared in this scope
    8 |     cin >> a >> b;
      |            ^
a.cc:8:17: error: 'b' was not declared in this scope
    8 |     cin >> a >> b;
      |                 ^
a.cc:9:7: error: expected ';' before 'mid'
    9 |     ll mid = (a+b) / 2;
      |       ^~~~
      |       ;
a.cc:10:7: error: expected ';' before 'ans1'
   10 |     ll ans1 = abs(a-mid);
      |       ^~~~~
      |       ;
a.cc:11:7: error: expected ';' before 'ans2'
   11 |     ll ans2 = abs(b-mid);
      |       ^~~~~
      |       ;
a.cc:12:8: error: 'ans1' was not declared in this scope
   12 |     if(ans1 == ans2) cout << mid << endl;
      |        ^~~~
a.cc:12:16: error: 'ans2' was not declared in this scope
   12 |     if(ans1 == ans2) cout << mid << endl;
      |                ^~~~
a.cc:12:30: error: 'mid' was not declared in this scope
   12 |     if(ans1 == ans2) cout << mid << endl;
      |                              ^~~
Language: C++


foo :: Int -> Int -> String
foo x y
  | even (x + y) = show $ div (x+y) 2
  | otherwise = "IMPOSSIBLE"

main = do
  xy <- map read . words <$> getLine :: IO [Int]
  putStrLn $ foo (head xy) (last xy)




Compiler output:
a.cc:2:1: error: 'foo' does not name a type
    2 | foo :: Int -> Int -> String
      | ^~~
Language: C++


foo :: Int -> Int -> String
foo x y
  | even (x + y) = show $ (x+y) `div` 2
  | otherwise = "IMPOSSIBLE"

main = do
  xy <- map read . words <$> getLine :: IO [Int]
  putStrLn $ foo (head xy) (last xy)




Compiler output:
a.cc:4:33: error: stray '`' in program
    4 |   | even (x + y) = show $ (x+y) `div` 2
      |                                 ^
a.cc:4:37: error: stray '`' in program
    4 |   | even (x + y) = show $ (x+y) `div` 2
      |                                     ^
a.cc:2:1: error: 'foo' does not name a type
    2 | foo :: Int -> Int -> String
      | ^~~
Language: C++

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
int main(){
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    ios_base::sync_with_stdio(0);
    int a,b;
    cin>>a>>b;
    inr c=abs(a-b);
    if(c%2)cout<<"IMPOSSIBLE";
    else cout<<c/2;
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:12:5: error: 'inr' was not declared in this scope; did you mean 'int'?
   12 |     inr c=abs(a-b);
      |     ^~~
      |     int
a.cc:13:8: error: 'c' was not declared in this scope
   13 |     if(c%2)cout<<"IMPOSSIBLE";
      |        ^
Language: Java

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		long a = s.nextLong();
		long b = s.nextLong();
		s.close();
		long disA = 0;
		long disB = 0;
		
		if(a < 0) {
			disA = a * -1;
		}else {
			disA = a;
		}
		if(b < 0) {
			disB = b * -1;
		}else {
			disB = b;
		}
		
		long judge = (disA + disB) % 2;
		if(judge == 1) {
			System.out.println("IMPOSSIBLE");
		}else {
			long disC = (disA + disB)/2;
			System.out.println(disC);
		}
		
	}

Compiler output:
Main.java:32: error: reached end of file while parsing
	}
	 ^
1 error
Language: C++

#inlcude<bits/stdc++.h>
using namespace std;
long long a,b,k;
int main()
{
	cin>>a>>b;
	if((a+b)%2==0)
	cout<<(a+b)/2;
	else
	cout<<"IMPOSSIBLE";
	return 0; 
}

Compiler output:
a.cc:1:2: error: invalid preprocessing directive #inlcude; did you mean #include?
    1 | #inlcude<bits/stdc++.h>
      |  ^~~~~~~
      |  include
a.cc: In function 'int main()':
a.cc:6:9: error: 'cin' was not declared in this scope
    6 |         cin>>a>>b;
      |         ^~~
a.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | #inlcude<bits/stdc++.h>
a.cc:8:9: error: 'cout' was not declared in this scope
    8 |         cout<<(a+b)/2;
      |         ^~~~
a.cc:8:9: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:10:9: error: 'cout' was not declared in this scope
   10 |         cout<<"IMPOSSIBLE";
      |         ^~~~
a.cc:10:9: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
Language: C++

#include<iostream>
using namespace std;
long int a, b;
cin >> a >> b;
if((a+b)%2==1)
  cout << "IMPOSSIBLE";
else cout << (a+b)/2;

Compiler output:
a.cc:4:1: error: 'cin' does not name a type
    4 | cin >> a >> b;
      | ^~~
a.cc:5:1: error: expected unqualified-id before 'if'
    5 | if((a+b)%2==1)
      | ^~
a.cc:7:1: error: expected unqualified-id before 'else'
    7 | else cout << (a+b)/2;
      | ^~~~
Language: C++

#include<iostream>
include namespace std;
long int a, b;
cin >> a >> b;
if((a+b)%2==1)
  cout << "IMPOSSIBLE";
else cout << (a+b)/2;

Compiler output:
a.cc:2:1: error: 'include' does not name a type
    2 | include namespace std;
      | ^~~~~~~
a.cc:4:1: error: 'cin' does not name a type
    4 | cin >> a >> b;
      | ^~~
a.cc:5:1: error: expected unqualified-id before 'if'
    5 | if((a+b)%2==1)
      | ^~
a.cc:7:1: error: expected unqualified-id before 'else'
    7 | else cout << (a+b)/2;
      | ^~~~
Language: C++

#include<iostream>
including namespace std;
long int a, b;
cin >> a >> b;
if((a+b)%2==1)
  cout << "IMPOSSIBLE";
else cout << (a+b)/2;

Compiler output:
a.cc:2:1: error: 'including' does not name a type
    2 | including namespace std;
      | ^~~~~~~~~
a.cc:4:1: error: 'cin' does not name a type
    4 | cin >> a >> b;
      | ^~~
a.cc:5:1: error: expected unqualified-id before 'if'
    5 | if((a+b)%2==1)
      | ^~
a.cc:7:1: error: expected unqualified-id before 'else'
    7 | else cout << (a+b)/2;
      | ^~~~
Language: C++

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

int main() {
  int a, b, n = 0;
  cin >> a >> b;
 if(a < b) swap(a, b);//必ずaのほうが大きい
  n = (a + b) / 2;
  if( (a + b) / 2 % 2 != 0) cout << "IMPOSSIBLE" << endl;
   n = (a + b) / 2;
  else cout << n << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:11:3: error: 'else' without a previous 'if'
   11 |   else cout << n << endl;
      |   ^~~~
Language: C++

#include <bits/stdc++.h>
int main(){
  int a, b;
  cin a >> b;
  if ((a + b) % 2 == 0){
    cout << a + b / 2 << endl;
   }else{
    cout << "IMPOSSIBLE" << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:4:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    4 |   cin a >> b;
      |   ^~~
      |   std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:6:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    6 |     cout << a + b / 2 << endl;
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:6:26: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    6 |     cout << a + b / 2 << endl;
      |                          ^~~~
      |                          std::endl
In file included from /usr/include/c++/14/istream:41,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:8:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    8 |     cout << "IMPOSSIBLE" << endl;
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:8:29: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    8 |     cout << "IMPOSSIBLE" << endl;
      |                             ^~~~
      |                             std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define pb push_back
typedef long long ll;
typedef long double ld;
#define FOR(i,n) for(i=0;i<n;i++)
#define FORE(i,n) for(i=0;i<=n;i++)
 
 
ll gcd(ll a , ll b)
{
   if(b==0) return a;
   a%=b;
   return gcd(b,a);
}

ll maxl(ll a,ll b){
    if(a>b)return a;
    return b;
}

ll mulmod(ll a, ll b, ll mod){ 
    ll res = 0; 
    a = a % mod; 
    while (b > 0){ 
        if (b % 2 == 1){ 
            res = (res + a) % mod;
        }
        a = (a * 2) % mod; 
        b /= 2; 
    } 
    return res % mod; 
} 

 
int main()
{
	ios_base::sync_with_stdio(false);
	int a,b;
	cin >> a >> b;
	if((a+b)%2){
	    cout << "IMPOSSIBLE" << endl;
	    return 0;
	}
	else{
	    cout << (a+b)/2 << endl;
	}
    return 0;
}

Compiler output:
a.cc:3:13: error: expected ',' or '...' before numeric constant
    3 | #define mod 1000000007
      |             ^~~~~~~~~~
a.cc:23:26: note: in expansion of macro 'mod'
   23 | ll mulmod(ll a, ll b, ll mod){
      |                          ^~~