542.cpp

// bruteForce.cpp
class Solution {
  int row, col;
  bool valid(int x, int y) {
    if (x < 0 || x >= row || y < 0 || y >= col)
      return 0;
    return 1;
  }
  int bruteForce(vector<vector<int>> &matrix, int i, int j) {
    int len = 1;
    while (1) {
      int x = 0, y = len;
      while (0 <= y) {
        if ((valid(i + x, j + y) && matrix[i + x][j + y] == 0) ||
            (valid(i - x, j + y) && matrix[i - x][j + y] == 0) ||
            (valid(i + x, j - y) && matrix[i + x][j - y] == 0) ||
            (valid(i - x, j - y) && matrix[i - x][j - y] == 0))
          return len;
        x++, y--;
      }
      ++len;
    }
  }

public:
  vector<vector<int>> updateMatrix(vector<vector<int>> &matrix) {
    row = matrix.size();
    col = matrix[0].size();
    vector<vector<int>> res(row, vector<int>(col, 0));
    for (int i = 0; i < row; ++i)
      for (int j = 0; j < col; ++j)
        if (matrix[i][j])
          res[i][j] = bruteForce(matrix, i, j);
    return res;
  }
};