59. 螺旋矩阵 II

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59. 螺旋矩阵 II

Description

Difficulty: 中等

Related Topics: 数组, 矩阵, 模拟

给你一个正整数 n ，生成一个包含 1 到 n² 所有元素，且元素按顺时针顺序螺旋排列的 n x n 正方形矩阵 matrix 。

示例 1：

输入：n = 3
输出：[[1,2,3],[8,9,4],[7,6,5]]

示例 2：

输入：n = 1
输出：[[1]]

提示：

• 1 <= n <= 20

Solution

Language: JavaScript

/**
 * @param {number} n
 * @return {number[][]}
 */
var generateMatrix = function(n) {
    let left = 0
    let right = n - 1
    let bottom = n - 1
    let top = 0
    const total = n * n

    const dep = []

    for (let i = 0; i < n; i++) {
        dep[i] = []
    }

    let count = 0

    while (count < total) {
        for (let i = left; i <= right; i++) dep[left][i] = ++count
        top++
        for (let i = top; i <= bottom; i++) dep[i][right] = ++count
        right--
        for (let i = right; i >= left; i--) dep[bottom][i] = ++count
        bottom--
        for (let i = bottom; i >= top; i--) dep[i][left] = ++count
        left++
    }

    return dep
};