Untitled

class Solution { //ANY REGIONS NOT CONNECTED TO THE BORDER WILL BE FLOODED
public:
    void dfs(vector<vector<char>>& board,int x,int y){
        if(x<0 || x>=board.size() || y<0 || y>=board[0].size() || board[x][y]!='O') return;
        board[x][y]='T';
        dfs(board,x-1,y);
        dfs(board,x+1,y);
        dfs(board,x,y-1);
        dfs(board,x,y+1);
    }

    void solve(vector<vector<char>>& board) {
        int r=board.size(), c=board[0].size();
        for(int i=0;i<r;i++){
            if(board[i][c-1]=='O') dfs(board,i,c-1);
            if(board[i][0]=='O') dfs(board,i,0);
        }

        for(int i=0;i<c;i++){
            if(board[0][i]=='O') dfs(board,0,i);
            if(board[r-1][i]=='O') dfs(board,r-1,i);
        }
        //every safe has been marked , now mark erevything else as X
        for(int i=0;i<r;i++){
            for(int j=0;j<c;j++){
                if(board[i][j]=='O') board[i][j]='X';
            }
        }
        for(int i=0;i<r;i++){
            for(int j=0;j<c;j++){
                if(board[i][j]=='T') board[i][j]='O';
            }
        }

 
    }
};


/***************************************************************

class Solution { //WRONG APPROACH
public:
    bool up(vector<vector<char>>& board,int x,int y){ //returns true if surrounded by X on up
        while(x>=0){
            if(board[x][y]=='X') {
                return true;
            }
            x--;
        }
        return false;
    }

    bool down(vector<vector<char>>& board,int x,int y){
        int r=board.size();
        while(x<r){
            if(board[x][y]=='X') return true;
            x++;
        }
        return false;
    }

    bool left(vector<vector<char>>& board,int x,int y){
        while(y>=0){
            if(board[x][y]=='X') return true;
            y--;
        }
        return false;
    }
    bool right(vector<vector<char>>& board,int x,int y){
        int c=board[0].size();
        while(y<c){
            if(board[x][y]=='X') return true;
            y++;
        }
        return false;
    }

    void solve(vector<vector<char>>& board) {
        int r=board.size();
        int c=board[0].size();
        for(int i=0;i<r;i++){
            for(int j=0;j<c;j++){
                if(board[i][j]=='O' && left(board,i,j) && right(board,i,j) && up(board,i,j) && down(board,i,j)) board[i][j]='X';
            }
        }
    }
}; */