顺时针打印矩阵

 1 class Solution {
 2 public:
 3     vector<int> printMatrix(vector<vector<int> > matrix) {
 4         vector<int> result;
 5             if (matrix.size() == 0)
 6                 return result;
 7             int len1 = matrix[0].size();
 8             int len2 = matrix.size() -1;
 9             int j,i = 0;
10             for ( j = 0; j < len1 ; ++j)
11             {
12                 result.push_back(matrix[i][j]);
13             }
14             --len1;
15             --j;
16             while(len1 >= 0 && len2 >= 0)
17             {
18                 for(int k = 0 ; k < len2 ; ++k)
19                 {
20                     ++ i;
21                     result.push_back(matrix[i][j]);
22                 }
23                 --len2;
24                 if (len2 <0)
25                     break;
26                 
27                 for(int k = 0 ; k < len1 ; ++k)
28                 {
29                     -- j;
30                     result.push_back(matrix[i][j]);
31                 }
32                 --len1;
33                 if (len1 <0)
34                     break;
35                 
36                 
37                 for(int k = 0 ; k < len2 ; ++k)
38                 {
39                     -- i;
40                     result.push_back(matrix[i][j]);
41                 }
42                 
43                  --len2;
44                 if (len2 <0)
45                     break;
46                 
47                 for(int k = 0 ; k < len1 ; ++k)
48                 {
49                     ++ j;
50                     result.push_back(matrix[i][j]);
51                 }
52                 
53                 --len1;
54                 if (len1 <0)
55                     break;
56             }
57             return result;
58     }
59 };