x 73. Set Matrix Zeroes

Set Matrix Zeroes - LeetCodeLeetCode

---> general solution

time: O(n x m)

space: O(1)

/**
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var setZeroes = function (matrix) {

    let firstRowZero = false;
    let firstColZero = false;

    for (let i = 0; i < matrix.length; i++) {
        for (let j = 0; j < matrix[0].length; j++) {
            const curr = matrix[i][j];
            if (curr !== 0) continue;

            if (i === 0) firstRowZero = true;
            if (j === 0) firstColZero = true;

            matrix[i][0] = 0;
            matrix[0][j] = 0;
        }
    }

    for (let i = 1; i < matrix.length; i++) {
        for (let j = 1; j < matrix[0].length; j++) {
            if (matrix[i][0] === 0 || matrix[0][j] === 0) {
                matrix[i][j] = 0;
            }
        }
    }

    if (firstRowZero) {
        for (let col = 0; col < matrix[0].length; col++) {
            matrix[0][col] = 0;
        }
    }
    if (firstColZero) {
        for (let row = 0; row < matrix.length; row++) {
            matrix[row][0] = 0;
        }
    }

    return matrix;
};

javascript solution

time: O(n^3)

space: O(1)

/**
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var setZeroes = function (matrix) {
    for (let i = 0; i < matrix.length; i++) {
        for (let j = 0; j < matrix[0].length; j++) {
            const curr = matrix[i][j];
            if (curr === 0) {
                for (let row = 0; row < matrix.length; row++) {
                    matrix[row][j] !== 0 && (matrix[row][j] = undefined);
                }
                for (let col = 0; col < matrix[0].length; col++) {
                    matrix[i][col] !== 0 && (matrix[i][col] = undefined);
                }
            }
        }
    }

    for (let i = 0; i < matrix.length; i++) {
        for (let j = 0; j < matrix[0].length; j++) {
            const curr = matrix[i][j];
            if (curr === undefined) {
                matrix[i][j] = 0;
            }
        }
    }

    return matrix;
};