Surrounded Regions

Given a 2D board containing 'X' and '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 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

class Solution {

public:

    void solve(vector<vector<char>> &tmp) 

    {

        int m=tmp.size();

        if(m==0) return;

        int n=tmp[0].size();

        //set 1 at edges

        for(int i=0;i<n;i++)

            if(tmp[0][i]=='O') tmp[0][i]=1;

        for(int i=0;i<n;i++)

            if(tmp[m-1][i]=='O') tmp[m-1][i]=1;

        for(int i=0;i<m;i++)

            if(tmp[i][0]=='O') tmp[i][0]=1;

        for(int i=0;i<m;i++)

            if(tmp[i][n-1]=='O') tmp[i][n-1]=1;

        while(true)

        {

            //get a '0' beside 1

            bool find=false;

            int i,j;

            for(i=0;i<m;i++)

            {

                for(j=0;j<n;j++)

                if(tmp[i][j]=='O')

                {

                    if(check(tmp,m,n,i-1,j,1) || check(tmp,m,n,i+1,j,1) ||check(tmp,m,n,i,j-1,1) ||check(tmp,m,n,i,j+1,1))

                    {

                        find=true;

                        break;

                    }

                }

                if(find) break;

            }

            if(!find) break;

            //fill

            while(tmp[i][j]=='O')

            {

                tmp[i][j]=1;

                if(check(tmp,m,n,i-1,j,'O'))

                {

                    i=i-1;continue;

                }

                if(check(tmp,m,n,i+1,j,'O'))

                {

                    i=i+1;continue;

                }

                if(check(tmp,m,n,i,j-1,'O'))

                {

                    j=j-1;continue;

                }

                if(check(tmp,m,n,i,j+1,'O'))

                {

                    j=j+1;continue;

                }

            }

        }

        for(int i=0;i<m;i++)

            for(int j=0;j<n;j++)

                if(tmp[i][j]==1)

                    tmp[i][j]='O';

                else

                    tmp[i][j]='X';

    }

    bool check(const vector<vector<char>> &tmp,int m,int n,int x,int y,char c)

    {

        if(x<0 || x>=m) return false;

        if(y<0 || y>=n) return false;

        if(tmp[x][y]==c) return true;

        return false;

    }

};