130. Surrounded Regions

​​'X'​​ and ​​'O'​​ (the letter O), capture all regions surrounded by ​​'X'​​.​​'O'​​s into ​​'X'​​s in that surrounded region.

For example,

X X X X X O O X X X O X X O X X

After running your function, the board should be:

X X X X X X X X X X X X X 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);
        }
    }
};