Set_Matrix_Zeroes.cpp

#include <bits/stdc++.h>

void setZeros(vector<vector<int>> &matrix)
{
    // Write your code here.
    int n = matrix.size();
    int m = matrix[0].size();
    int col0 = 1;
    // step 1: Traverse the matrix and
    // mark 1st row & col accordingly:
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            if (matrix[i][j] == 0)
            {
                // mark i-th row:
                matrix[i][0] = 0;

                // mark j-th column:
                if (j != 0)
                    matrix[0][j] = 0;
                else
                    col0 = 0;
            }
        }
    }

    // Step 2: Mark with 0 from (1,1) to (n-1, m-1):
    for (int i = 1; i < n; i++)
    {
        for (int j = 1; j < m; j++)
        {
            if (matrix[i][j] != 0)
            {
                // check for col & row:
                if (matrix[i][0] == 0 || matrix[0][j] == 0)
                {
                    matrix[i][j] = 0;
                }
            }
        }
    }

    // step 3: Finally mark the 1st col & then 1st row:
    if (matrix[0][0] == 0)
    {
        for (int j = 0; j < m; j++)
        {
            matrix[0][j] = 0;
        }
    }
    if (col0 == 0)
    {
        for (int i = 0; i < n; i++)
        {
            matrix[i][0] = 0;
        }
    }
}