0994-rotting-oranges.js

/**
 * https://leetcode.com/problems/rotting-oranges/
 * Time O(ROWS * COLS) | Space O(ROWS * COLS)
 * @param {number[][]} grid
 * @return {number}
 */
var orangesRotting = function (grid) {
    const { queue, orangeCount } = searchGrid(grid); /* Time O(ROWS * COLS) */
    const { rottenCount, minutes } = bfs(grid, queue);

    const isEqual = orangeCount === rottenCount;
    return isEqual ? minutes : -1;
};

const searchGrid = (grid, orangeCount = 0, queue = new Queue([])) => {
    const [rows, cols] = [grid.length, grid[0].length];

    for (let row = 0; row < rows; row++) {
        /* Time O(ROWS) */
        for (let col = 0; col < cols; col++) {
            /* Time O(COLS) */
            const isEmpty = grid[row][col] === 0;
            if (!isEmpty) orangeCount++;

            const isRotten = grid[row][col] === 2;
            if (isRotten) queue.enqueue([row, col]); /* Space O(ROWS * COLS) */
        }
    }

    return { queue, orangeCount };
};

const bfs = (grid, queue, rottenCount = 0, minutes = 0) => {
    while (!queue.isEmpty()) {
        rottenCount += queue.size();

        for (let i = queue.size() - 1; 0 <= i; i--) {
            /* Time O(WIDTH) */
            expireFresh(grid, queue);
        }

        if (queue.size()) minutes++;
    }

    return { rottenCount, minutes };
};

var expireFresh = (grid, queue) => {
    const [rows, cols] = [grid.length, grid[0].length];
    const [row, col] = queue.dequeue();

    for (const [_row, _col] of getNeighbors(row, rows, col, cols)) {
        const isFresh = grid[_row][_col] === 1;
        if (!isFresh) continue;

        grid[_row][_col] = 2;
        queue.enqueue([_row, _col]); /* Space O(ROWS * COLS) */
    }
};

var getNeighbors = (row, rows, col, cols) =>
    [
        [0, 1],
        [0, -1],
        [1, 0],
        [-1, 0],
    ]
        .map(([_row, _col]) => [row + _row, col + _col])
        .filter(
            ([_row, _col]) =>
                0 <= _row && _row < rows && 0 <= _col && _col < cols,
        );

/**
 * https://leetcode.com/problems/rotting-oranges/
 * Time O((ROWS * COLS)^2) | Space O(1)
 * @param {number[][]} grid
 * @return {number}
 */
var orangesRotting = function (grid, minutes = 2) {
    while (expireFresh(grid, minutes)) minutes++; /* Time O((ROWS * COLS)^2) */

    return !hasFresh(grid) /* Time O(ROWS * COLS) */ ? minutes - 2 : -1;
};

var expireFresh = (grid, minutes, toBeContinued = false) => {
    const [rows, cols] = [grid.length, grid[0].length];

    for (let row = 0; row < rows; row++) {
        /* Time O(ROWS) */
        for (let col = 0; col < cols; col++) {
            /* Time O(COLS) */
            const isEqual = grid[row][col] === minutes;
            if (!isEqual) continue;

            for (const [_row, _col] of getNeighbors(row, rows, col, cols)) {
                const isFresh = grid[_row][_col] === 1;
                if (!isFresh) continue;

                grid[_row][_col] = minutes + 1;
                toBeContinued = true;
            }
        }
    }

    return toBeContinued;
};

var getNeighbors = (row, rows, col, cols) =>
    [
        [0, 1],
        [0, -1],
        [1, 0],
        [-1, 0],
    ]
        .map(([_row, _col]) => [row + _row, col + _col])
        .filter(
            ([_row, _col]) =>
                0 <= _row && _row < rows && 0 <= _col && _col < cols,
        );

const hasFresh = (grid) => {
    for (const row of grid) {
        /* Time O(ROWS) */
        for (const cell of row) {
            /* Time O(COLS) */
            const isFresh = cell === 1;
            if (isFresh) return true;
        }
    }

    return false;
};