题目

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，

例如，如果输入如下4 X 4矩阵：

1   2   3   4

5   6   7   8

9  10  11  12

13 14  15 16

则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.

思路

定下3个点，则做四次循环

1、start -> endX 

2、start+1 -> endY

3、endY-1 -> start

4、endY -> start - 1

 

取x为cols，rows中较小的，每做4次循环，x = x - 2

当 x > 0，循环才进行

start	.	.	.	endX
	.	.	.
	.	.	.
	.	.	.
	.	.	.	endY

 

 

 

 

 

class Solution {public:    vector
     
       printMatrix(vector
      
       
         > matrix) {        vector
        
          res;        int row=matrix.size();//行数        int col=matrix[0].size();//列数        int x = min(row, col), start = 0;        while ( x > 0){            int endX = col - 1 - start;            int endY = row - 1 - start;            for (int i = start; i <= endX; i++)                res.push_back(matrix[start][i]);                        if( start < endY){                for (int i = start +1 ; i <= endY; i++)                    res.push_back(matrix[i][endX]);            }                        if (start < endX && start < endY){                for (int i = endX - 1; i >= start; i--)                    res.push_back(matrix[endY][i]);            }                        if (start < endX && start < endY - 1){                for (int i =endY - 1; i > start; i--)                    res.push_back(matrix[i][start]);            }                        x = x - 2;            start++;        }        return res;    }};