202408272247
tags: #array #matrix

var spiralMatrixIII = function(rows, cols, rStart, cStart) {
	const DIRS = [[0, 1], [1, 0], [0, -1], [-1, 0]];
	const res = [[rStart, cStart]];
	let len = 0, direction = 0;
	let r = rStart, c = cStart;
	while (res.length < rows * cols) {
		if (direction === 0 || direction === 2) {
			len += 1;
		}
		for (let i = 0; i < len; i++) {
			r += DIRS[direction][0];
			c += DIRS[direction][1];
			if (r >= 0 && r < rows && c >= 0 && c < cols) {
				res.push([r, c]);
			}
		}
		direction = (direction + 1) % 4;
	}
	return res;
};

Reference

https://leetcode.com/problems/spiral-matrix-iii