My following solution for Leapfrog: Ch. 1 failed:

#include <iostream>
#include <string>
using namespace std;

int T;

int main() {
  cin >> T;
  
  for (int test = 1; test <= T; ++test)
  {
    string s;
    cin >> s;

    int n = s.length();
    int b = 0;
    for (int i = 0; i < n; i++)
      if (s[i] == 'B')
        b++;

    char yesno = ( b+1 <= n-1 && n-1 <= 2*b ?'Y' :'N');
    cout << "Case #" << test << ": " << yesno << "\n";
  }

  return 0;
}

I compared the outputs for the reference solution and mine. But they are the same. diff doesn't find any differences.

Here is the Dropbox folder with my and reference solution's sources, inputs and outputs. I don't believe I submitted the wrong files.

Can someone confirm or reject the validity of my solution?