25 December Missing number in matrix

class Solution {
public:
    long long int MissingNo(vector<vector<int> >& matrix) {
     set<long long int>nonzero, zero;
     
     // Interating through rows
     for(int i = 0; i < matrix.size(); i++){
      bool f = true;
      long long int sum = 0;
      for(int j = 0; j < matrix[0].size(); j++){
       sum += matrix[i][j];
       if(!matrix[i][j])
        f = false;
      }
      if(f)nonzero.insert(sum);
      if(!f)zero.insert(sum);
     }
     // Interating through coloumns
     for(int  j = 0; j < matrix[0].size(); j++){
      bool f = true;
      long long int sum = 0;
      for(int i = 0; i < matrix.size(); i++){
       sum += matrix[i][j];
       if(!matrix[i][j])
        f = false;
      }
      if(f)nonzero.insert(sum);
      if(!f)zero.insert(sum);
     }
     // Interating through diagonals
     bool f = true;
     long long int sum = 0;
     for(int i = 0; i < matrix.size(); i++){
      sum += matrix[i][i];
      if(!matrix[i][i])
       f = false;
     }
     if(f)nonzero.insert(sum);
  if(!f)zero.insert(sum);
     // Interating through diagonals
     f = true;
     sum = 0;
     for(int i = 0, j = matrix.size() - 1; j >= 0; i++,j--){
      sum += matrix[i][j];
      if(!matrix[i][j])
       f = false;
     }
  if(f)nonzero.insert(sum);
  if(!f)zero.insert(sum);
     if(nonzero.size() == 1 and zero.size() == 1){
      long long int x = *nonzero.begin();
      long long int y = *zero.begin();
      if(x <= y)
       return -1;
      return x - y;
     }
     return -1;
    }
};