sortedmatrix X21748

  14: #include <iostream>
  15: #include <vector>
  16:
  17: typedef std::vector<std::vector<int> > Matrix;
  18:
  19: bool sortedmatrix(const Matrix& M) {
  20:     if(!M.size() || !M.at(0).size()) return true; // If matrix is null return true
  21:     std::vector<int> vec_columns = M.at(0); // We create an auxiliar vector to avoid check twice the matrix copying it from first row
  22:     for(int x = 0; x < M.size(); x++) {
  23:         int n_row = M[x][0]; //we load first value
  24:         for(int y = 0; y < M.at(0).size(); y++) {
  25:             //We check that the row is ascending otherwise return false
  26:             if(n_row <= M[x][y]) n_row = M[x][y]; else return false;
  27:             //We check that the column is ascending too otherwise return false
  28:             if(vec_columns[y] <= M[x][y]) vec_columns[y] = M[x][y]; else return false;
  29:         }
  30:     }
  31:     return true; //It's sorted, return true
  32: }
  33:
  34: int main() {
  35:     int n, m;
  36:     while(std::cin >> n >> m) { //load matrix size
  37:         Matrix matrix(n, std::vector<int>(m)); //Initialize the matrix
  38:         //load the matrix
  39:         for(int x = 0; x < n; x++)
  40:             for(int y = 0; y < m; y++)
  41:                 std::cin >> matrix[x][y];
  42:         //we check if it's sorted
  43:         if(sortedmatrix(matrix))
  44:             std::cout << "yes" << std::endl;
  45:         else
  46:             std::cout << "no" << std::endl;
  47:     }
  48:     return 0;
  49: }