130. Surrounded Regions

Given a 2D board containing 'X' and 'O' (the letter O), capture all regions surrounded by 'X'.

A region is captured by flipping all 'O's into 'X's in that surrounded region.

For example,

X X X XX O O XX X O XX O X X

After running your function, the board should be:

X X X XX X X XX X X XX O X X

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还是深度搜索连通子图类的问题

类似题200. Number of Islands（重要）

class Solution {public:void solve(vector<vector<char>>& board) {        int i,j;        int row=board.size();        if(!row)        return;        int col=board[0].size();for(i=0;i<row;i++){check(board,i,0,row,col);if(col>1)check(board,i,col-1,row,col);}for(j=1;j+1<col;j++){check(board,0,j,row,col);if(row>1)check(board,row-1,j,row,col);}for(i=0;i<row;i++)for(j=0;j<col;j++)if(board[i][j]=='O')board[i][j]='X';for(i=0;i<row;i++)for(j=0;j<col;j++)if(board[i][j]=='1')board[i][j]='O';    }void check(vector<vector<char> >&vec,int i,int j,int row,int col){if(vec[i][j]=='O'){vec[i][j]='1';if(i>1)check(vec,i-1,j,row,col);if(j>1)check(vec,i,j-1,row,col);if(i+1<row)check(vec,i+1,j,row,col);if(j+1<col)check(vec,i,j+1,row,col);}}};