Tell me whats wrong in this approach to this problem i wrote for this problem I am just a beginner.

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#include<iostream>
using namespace std;
 
int main(){
    long long int t;
    cin>>t;
    while (t--)
    {
        long long int x , y;
        cin>>x>>y;
 
        if(x == y) cout<<x*(x-1) + 1<<"\n" ;
        if(x>y) 
        {
            long long int diag = x*(x -1) +1;
            cout<<diag + (x - y)<<"\n";
        }
        if(x<y) cout<< y*(y-1) + 1 + (y-x)<<"\n";
    }

~~~~~