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LeetCode day317–73

Everyday has one random leetcode quiz. Today’s quiz is 73. Set Matrix Zeroes

Description:

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.

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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]]

We use zeroRow and zeroColumn to record which row or column need to be set as 0 .

Check entire matrix , mark these 0 cell’s row and column as true .

Check entire matrix again, update cell by zeroRow and zeroColumn .

If matrix is n*m, the time complexity is O(n*m)

/**
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var setZeroes = function (matrix) {
    const zeroRow = Array(matrix.length).fill(false)
    const zeroColumn = Array(matrix[0].length).fill(false)

    for (let row = 0; row < matrix.length; row++) {
        for (let col = 0; col < matrix[0].length; col++) {
            if (matrix[row][col] === 0) {
                zeroRow[row] = true
                zeroColumn[col] = true
            }
        }
    }

    for (let row = 0; row < matrix.length; row++) {
        for (let col = 0; col < matrix[0].length; col++) {
            if (zeroRow[row] || zeroColumn[col]) {
                matrix[row][col] = 0
            }
        }
    }
};