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]

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/shun-shi-zhen-da-yin-ju-zhen-lcof
著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

class Solution {
    public int[] spiralOrder(int[][] matrix) {
        
        if(matrix == null ||matrix.length == 0){
            return new int[0];
        }
        
        //初始化
        int left = 0, top = 0;
        int right = matrix[0].length-1;
        int bottom = matrix.length - 1;
        int[] res = new int[(right+1)*(bottom+1)];
        int k = 0;
        
        //循环打印
        while(top <= bottom && left <= right){
            for(int i = left; i <= right; i++){ //左到右
                res[k++] = matrix[top][i];
            }
            top ++;   //假设第一遍的时候，top++代表第一行已经走完
            for(int i = top; i <= bottom; i++){ //上到下
                res[k++] = matrix[i][right];
            }
            right --;
            for(int i = right; i >= left && top <= bottom; i--){    //右到左
                res[k++] = matrix[bottom][i];
            }
            bottom --;
            for(int i = bottom; i >= top && left <= right; i--){    //下到上
                res[k++] = matrix[i][left];
            }
            left ++;
        }
        return res;
    }
}

剑指 Offer 29. 顺时针打印矩阵

原文：https://www.cnblogs.com/xiaofff/p/14221611.html