What went wrong in my code

[arian892]

My issue

My code

#include <iostream>
using namespace std;

     int n, m ; 
     int r ; 
     int t ; 
  
    int t1 ;
    unsigned long long int sum=0 ;
    unsigned long long int ans= 0 ;

int main() {
   
    cin >> t ; 
     
    while (t--)
    {
       
        
        sum = 0 ; 
        cin >> n >> m ; 
        
        for (int i= 0 ; i< m ; i++)
        {
            cin >> t1 ; 
            sum += t1 ; 
             
        }
         ans = (((n*(n+1))/2) - sum ) ; 
         cout <<  ans << endl ; 
    }
      return 0;
}

Problem Link: REMOVEMUL Problem - CodeChef

[labu_1011]

Facing the same issue. Used long long int. still got WA

[lightrajat]

This would solve your problem…

What's wrong in my code for REMOVEMUL problem

In the line: long long int sumN = n*(n+1) / 2; the left side of the expression is long long int. On the right side, n is an int. So, n + 1 is also an int. Then n * (n+1) (int * int) will also has to be an int, which in some cases would exceed the int datatype capacity. This would result in a strange value, which would still be int. Only after diving by 2 (int), it would implicilty convert to long long int datatype. To resolve this, just use- long long int sumN = n*(n+1LL) / 2; This would m…

[navihere01]

make everything long long