LeetCode Surrounded Regions 

 // 56ms
 1 class Solution {
 2 public:
 3     
 4     void DFS(vector<vector<char>> &v,int i,int j)
 5     {
 6         if(v[i][j]=='O')
 7         {
 8             v[i][j]='Q';
 9             if(i>0)
10                 DFS(v,i-1,j);
11             if(i<v.size()-1)
12                 DFS(v,i+1,j);
13             if(j>0)
14                 DFS(v,i,j-1);
15             if(j<v[i].size())
16                 DFS(v,i,j+1);           
17         }
18     }
19     void flagS(vector<vector<char>> &v)
20     {
21         int i,j;
22         for(j=0;j<v[0].size();j++)
23         {
24             DFS(v,0,j);
25             DFS(v,v.size()-1,j);
26         }
27         for(i=1;i<v.size()-1;i++)
28         {
29             DFS(v,i,0);
30             DFS(v,i,v[i].size()-1);
31         }
32         
33     }
34     void flag(vector<vector<char>> &v)
35     {
36         int i,j;
37         for(i=0;i<v.size();i++)
38         {
39             for(j=0;j<v[i].size();j++)
40             {
41                 if(v[i][j]=='O')
42                     v[i][j]='X';
43                 if(v[i][j]=='Q')
44                     v[i][j]='O';
45             }
46         }
47     }
48     void solve(vector<vector<char>> &board) {
49         // Start typing your C/C++ solution below
50         // DO NOT write int main() function
51         if(board.size()==0)
52             return;
53         flagS(board);
54         flag(board);
55         
56     }
57 };

 

posted on 2013-06-03 10:47  宇睿  阅读(131)  评论(0)  编辑  收藏  举报