1 class Solution {
2 public:
3 vector<int> printMatrix(vector<vector<int> > matrix) {
4 vector<int> result;
5 if(matrix.empty()) return result;
6 int rows = matrix.size();
7 int cols = matrix[0].size();
8 //定义四个角标
9 int left = 0;
10 int right = cols-1;
11 int top_row = 0;
12 int end_row = rows-1;
13 while(left<=right && top_row<=end_row){
14 //打印第一行
15 for(int i=left;i<=right;i++) result.push_back(matrix[top_row][i]);
16 //打印右边的列
17 //判断边界，如果只有一行的情况就不push了
18 if(top_row<end_row){
19 for(int i=top_row+1;i<=end_row;i++) result.push_back(matrix[i][right]);
20 }
21 //打印最下面一行
22 //判断边界
23 if(left<right && top_row<end_row){
24 for(int i=right-1;i>=left;i--) result.push_back(matrix[end_row][i]);
25 }
26 //打印左边一列
27 //判断边界
28 if(top_row+1<end_row && left<right){
29 for(int i=end_row-1;i>=top_row+1;i--) result.push_back(matrix[i][left]);
30 }
31 left++;right--;top_row++;end_row--;
32 }
33 return result;
34 }
35 };
