202408211447
tags: #bfs

var wallsAndGates = function(rooms) {
	const INF = 2147483647;
	const m = rooms.length;
	const n = rooms[0].length;
	const DIRS = [[1, 0], [0, 1], [-1, 0], [0, -1]];
	const q = [];
	for (let i = 0; i < m; i++) {
		for (let j = 0; j < n; j++) {
			if (rooms[i][j] === 0) {
				q.push([i, j]);
			}
		}
	}
	while (q.length > 0) {
		const [i, j] = q.shift();
		for (const [dx, dy] of DIRS) {
			const x = i + dx;
			const y = j + dy
			if (x < 0 || y  0 || x >= m || y >= n || rooms[x][y] !== INF) {
				continue;
			}
			rooms[x][y] = rooms[i][j] + 1;
			q.push([x, y]);
		}
	}
};

Reference

https://leetcode.com/problems/walls-and-gates