Set Matrix Zeroes


Problem Statement :


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 :



title-img 


                            Solution in C :

void setZeroes(int** matrix, int matrixSize, int* matrixColSize) 
{
     bool row_flag = false, col_flag = false;
     int row = matrixSize, col = *matrixColSize;

    // Mark col_flag true if entire col will need to be zeroed out
     for(int r = 0; r < row; r++)
     {
         if(matrix[r][0] == 0)
         {
             col_flag = true;
             break;
         }
     }
    // Mark row_flag true if entire row will need to be zeroed out
     for(int c = 0; c < col; c++)
     {
         if(matrix[0][c] == 0)
         {
             row_flag = true;
             break;
         }
     }
    
    // If matrix[i][j] is '0', mark corresponding [0th row][0th col] element as zero
    for(int r = 1; r < row; r++)
    {
        for(int c = 1; c < col; c++)
        {
            if(matrix[r][c] == 0)
            {
                matrix[0][c] = matrix[r][0] = 0;
            }
        }
    }

    // If corresponding [0th row][0th col] is 0, make matrix[r][c] = 0
    for(int r = 1; r < row; r++)
    {
        for(int c = 1; c < col; c++)
        {
            if(matrix[r][0] == 0 || matrix[0][c] == 0)
            {
                matrix[r][c] = 0;
            }
        }
    }

    if(col_flag == true)
    {
        for(int r = 0; r < row; r++)
        {
            matrix[r][0] = 0;
        }
    }

    if(row_flag == true)
    {
        for(int c = 0; c < col; c++)
        {
            matrix[0][c] = 0;
        }
    }
}
                        


                        Solution in C++ :

class Solution {
public:
    void setZeroes(vector<vector<int>>& matrix) {
        vector<pair<int, int>> V;
        int n = matrix.size();
        int m = matrix[0].size();

        for (int i=0; i<n; i++)
        {
            for (int j=0; j<m; j++)
            {
                if (matrix[i][j] == 0)
                    V.push_back({i, j});
            }
        }

        for (auto p : V)
        {
            int row = p.first;
            int col = p.second;

            matrix[row].assign(m, 0);

            for (int i=0; i<n; i++)
                matrix[i][col] = 0;
        }

    }
};
                    


                        Solution in Java :

class Solution {
    public void setZeroes(int[][] matrix) {
        int n = matrix.length;
        int m = matrix[0].length;

        List<Pair<Integer, Integer>> V = new ArrayList<>();

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (matrix[i][j] == 0)
                    V.add(new Pair<>(i, j));
            }
        }

        for (Pair<Integer, Integer> p : V) {
            int row = p.getKey();
            int col = p.getValue();

            for (int i = 0; i < m; i++)
                matrix[row][i] = 0;

            for (int i = 0; i < n; i++)
                matrix[i][col] = 0;
        }
    }
}
                    


                        Solution in Python : 
                            
from typing import List

class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        n = len(matrix)
        m = len(matrix[0])

        V = []

        for i in range(n):
            for j in range(m):
                if matrix[i][j] == 0:
                    V.append((i, j))

        for row, col in V:
            matrix[row] = [0] * m

            for i in range(n):
                matrix[i][col] = 0


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