54.螺旋矩阵.js

/*
 * @lc app=leetcode.cn id=54 lang=javascript
 *
 * [54] 螺旋矩阵
 *
 * https://leetcode-cn.com/problems/spiral-matrix/description/
 *
 * algorithms
 * Medium (48.67%)
 * Likes:    1087
 * Dislikes: 0
 * Total Accepted:    258.9K
 * Total Submissions: 531.3K
 * Testcase Example:  '[[1,2,3],[4,5,6],[7,8,9]]'
 *
 * 给你一个 m 行 n 列的矩阵 matrix ，请按照 顺时针螺旋顺序 ，返回矩阵中的所有元素。
 *
 *
 *
 * 示例 1：
 *
 *
 * 输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
 * 输出：[1,2,3,6,9,8,7,4,5]
 *
 *
 * 示例 2：
 *
 *
 * 输入：matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
 * 输出：[1,2,3,4,8,12,11,10,9,5,6,7]
 *
 *
 *
 *
 * 提示：
 *
 *
 * m == matrix.length
 * n == matrix[i].length
 * 1
 * -100
 *
 *
 */

// @lc code=start
/**
 * @param {number[][]} matrix
 * @return {number[]}
 */
var spiralOrder = function (matrix) {
	let direction = "right",
		left = 0,
		right = matrix[0].length - 1,
		top = 0,
		bottom = matrix.length - 1;
	const ans = [];
	while (left <= right && top <= bottom) {
		if (direction === "right") {
			for (let i = left; i <= right; i++) {
				ans.push(matrix[top][i]);
			}
			direction = "down";
			top++;
		} else if (direction === "down") {
			for (let i = top; i <= bottom; i++) {
				ans.push(matrix[i][right]);
			}
			direction = "left";
			right--;
		} else if (direction === "left") {
			for (let i = right; i >= left; i--) {
				ans.push(matrix[bottom][i]);
			}
			direction = "up";
			bottom--;
		} else if (direction === "up") {
			for (let i = bottom; i >= top; i--) {
				ans.push(matrix[i][left]);
			}
			direction = "right";
			left++;
		}
	}

	return ans;
};
// @lc code=end