Spiral Matrix

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,
Given the following matrix:

[
 [ 1, 2, 3 ],
 [ 4, 5, 6 ],
 [ 7, 8, 9 ]
]

You should return [1,2,3,6,9,8,7,4,5].

思路：

取长和宽里比较小的一个值，逐层输出，剩余一层再单独判断。

代码：

 1     int min(int a, int b){
 2         if(a < b)
 3             return a;
 4         return b;
 5     }
 6     vector<int> spiralOrder(vector<vector<int> > &matrix) {
 7         // IMPORTANT: Please reset any member data you declared, as
 8         // the same Solution instance will be reused for each test case.
 9         vector<int> result;
10         result.clear();
11         int m = matrix.size();
12         if(m == 0)
13             return result;
14         int n = matrix[0].size();
15         if(n == 0)
16             return result;
17         int i,j;
18         for(i = 0; i < min(m,n)/2; i++){
19             for(j = i; j < n-1-i; j++)
20                 result.push_back(matrix[i][j]);
21             for(j = i; j < m-1-i; j++)
22                 result.push_back(matrix[j][n-1-i]);
23             for(j = n-1-i; j > i; j--)
24                 result.push_back(matrix[m-1-i][j]);
25             for(j = m-1-i; j > i; j--)
26                 result.push_back(matrix[j][i]);
27         }
28         if(min(m,n)%2 == 1){
29             if(m < n){
30                 for(i = m/2; i < n-m/2; i++)
31                     result.push_back(matrix[m/2][i]);
32             }
33             else{
34                 for(i = n/2; i < m-n/2; i++)
35                     result.push_back(matrix[i][n/2]);
36             }
37         }
38         return result;
39     }