LeetCode OJ：Spiral MatrixII（螺旋矩阵II）

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

For example,
Given n = 3,

You should return the following matrix:

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

依旧是dfs问题，代码如下所示：

 1 class Solution {
 2 public:
 3     vector<vector<int>> generateMatrix(int n) {
 4         vector<vector<int>>ret(n, vector<int>(n, 0));
 5         vector<vector<bool>>mark(n, vector<bool>(n,false));
 6         if(!n) return ret;
 7         dfs(ret, mark, 0, -1, n, 0, 1);
 8         return ret;
 9     }
10 
11     void dfs(vector<vector<int>> & ret, vector<vector<bool>> & mark, int i, int j, int n, int curr, int currVal)
12     {
13         for(int k = 0; k < 4; ++k){
14             int dirct = (curr + k) % 4;
15             int ii = i + drct[dirct][0];
16             int jj = j + drct[dirct][1];
17             if(ii >= 0 && ii < n && 
18                 jj >= 0 && jj < n &&
19                 mark[ii][jj] == false){
20                 mark[ii][jj] = true;
21                 ret[ii][jj] = currVal;
22                 dfs(ret, mark, ii, jj, n, dirct, currVal + 1);
23             }
24 
25         }
26     }   
27 
28 private:
29     vector<vector<int>>drct = {{0,1},{1,0},{0,-1},{-1,0}};
30 };

代码写的比较乱，凑合着看哈哈 

posted @ 2015-11-03 11:53  eversliver  阅读(231)  评论(0)  编辑  收藏  举报