剑指Offer 29. 顺时针打印矩阵

模拟

class Solution {
    public int[] spiralOrder(int[][] matrix) {

        if (matrix.length == 0){
            return new int[0];
        }

        int m = matrix.length;
        int n = matrix[0].length;

        int[] arr = new int[m * n];

        int top = 0;
        int bottom = m - 1;
        int left = 0;
        int right = n - 1;

        int index = 0;

        while (index <= arr.length - 1){

            for (int i = left; i <= right && index <= arr.length - 1; i++) {
                arr[index++] = matrix[top][i];
            }

            top++;

            for (int i = top; i <= bottom && index <= arr.length - 1; i++) {
                arr[index++] = matrix[i][right];
            }

            right--;

            for (int i = right; i >= left && index <= arr.length - 1; i--) {
                arr[index++] = matrix[bottom][i];
            }

            bottom--;

            for (int i = bottom; i >= top && index <= arr.length - 1; i--) {
                arr[index++] = matrix[i][left];
            }

            left++;
        }

        return arr;
    }
}

/**
 * 时间复杂度 O(mn)
 * 空间复杂度 O(1)
 */

https://leetcode-cn.com/problems/shun-shi-zhen-da-yin-ju-zhen-lcof/