Set Matrix Zeroes - LeetCode Solution in C++

     

Set Matrix Zeroes

Given an m x n integer matrix matrix, if an element is 0, set its entire row and column to 0's.

You must do it in place.

Example 1:

Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
Output: [[1,0,1],[0,0,0],[1,0,1]]

Example 2:

Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]
Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]

 Constraints:

• m == matrix.length
• n == matrix[0].length
• 1 <= m, n <= 200
• -231 <= matrix[i][j] <= 231 - 1

 

Follow up:

• A straightforward solution using O(mn) space is probably a bad idea.
• A simple improvement uses O(m + n) space, but still not the best solution.
• Could you devise a constant space solution?

. . .
Solution in C++.

class Solution {
public:
    void setZeroes(vector<vector<int>>& m) {
        int rs = m.size();
        int cs = m[0].size();
        vector<int> row(rs, 1);
        vector<int> col(cs, 1);
        for (int i = 0; i < rs; i++) {
            for (int j = 0; j < cs; j++) {
                if (m[i][j] == 0) {
                    row[i] = 0;
                    col[j] = 0;
                }
            }
        }
        for (int i = 0; i < rs; i++) {
            for (int j = 0; j < cs; j++) {
                if (row[i] == 0 || col[j] == 0) {
                    m[i][j] = 0;
                }
            }
        }
    }
};



Try the solution on LeetCode: leetcode.com/problems/set-matrix-zeroes/