0994-rotting-oranges.ts

function orangesRotting(grid: number[][]): number {
    let [ROWS, COLS, time, fresh, q] = [grid.length, grid[0].length, 0, 0, []];
    let dirs = [
        [0, 1],
        [0, -1],
        [1, 0],
        [-1, 0],
    ];

    // count fresh oranges and add rotten oranges to queue
    for (let i = 0; i < ROWS; i++) {
        for (let j = 0; j < COLS; j++) {
            if (grid[i][j] === 1) {
                fresh++;
            }
            if (grid[i][j] === 2) {
                q.push([i, j]);
            }
        }
    }

    while (q.length > 0 && fresh > 0) {
        let qLen = q.length;

        for (let rot = 0; rot < qLen; rot++) {
            let [row, col] = q.shift();

            for (let dir of dirs) {
                let [r, c] = [row + dir[0], col + dir[1]];

                if (
                    r < 0 ||
                    r >= ROWS ||
                    c < 0 ||
                    c >= COLS ||
                    grid[r][c] !== 1
                ) {
                    continue;
                }

                grid[r][c] = 2;
                fresh--;
                q.push([r, c]);
            }
        }
        time++;
    }
    return fresh > 0 ? -1 : time;
}