SCORE_predictor

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1

My code solves the problem got correct for input but on submit shows wrong answer.
Problem: CodeChef: Practical coding for everyone
My Code:-

#include<iostream>
#include<string>

using namespace std;

int main(){

  int t;
  cin>>t;

  while(t--){
    int N;
    cin>>N;

    string input;
    cin>>input;

    int i{0}, j{1}, A{0}, B{0}, ans{0};

    for(int r=0; r<N; r++){
      A += ((int)input[i]-48);
      B += ((int)input[j]-48);
      i+=2;
      j+=2;
      if(A > ((N-r-1)+B) || B > ((N-r-1)+A)){
        ans = (r+1)*2;
        break;
      }
      ans = (r+1)*2;
    }

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

Please Help.