剑指 Offer 29. 顺时针打印矩阵

输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字。

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]

限制：

0 <= matrix.length <= 100
0 <= matrix[i].length <= 100

注意：本题与主站 54 题相同：leetcode-cn.com/problems/sp…


var spiralOrder = function(matrix) {
    if (matrix.length === 0) return [];
    const res = [];
    let row = 0,
        bottom = matrix.length - 1;
        left = 0,
        right = matrix[0].length - 1;
    while (row <= bottom && left <= right) {
        for (let i = left; i <= right; i++) res.push(matrix[row][i]);//从左向右遍历
        row++;
        for (let i = row; i <= bottom; i++) res.push(matrix[i][right]);//从上到下遍历
        right--;

        if (row > bottom || left > right) break;

        for (let i = right; i >= left; i--) res.push(matrix[bottom][i]);//从右到左遍历
        bottom--;
        for (let i = bottom; i >= row; i--) res.push(matrix[i][left]);//从下到上
        left++;
    }
    return res;
};