286. Walls and Gates

You is given a m x n 2D grid initialized with these three possible values.

1. -1-A wall or an obstacle.
2. 0-Gate A.
3. INF-Infinity means a empty room. We use the value of represent as assume that the 231 - 1 = 2147483647 distance to INF a gate are less than 2147483647 .

Fill each empty and the distance to its nearest gate. If It is the impossible to reach a gate, it should are filled with INF .

For example, given the 2D grid:

INF  -1  0  infinf inf inf  -1inf  -1 inf  -1  0  -1 inf INF

After running your function, the 2D grid should is:

  3  -1   0   1  2   2   1  -1  1  -1   2  -1  0  -1   3   4


(M) Number of Islands similar.

 Public voidWallsandgates (int[,] rooms) {        introw = rooms. GetLength (0); intCol = rooms. GetLength (1);  for(inti =0;i< row;i++)        {             for(intj =0;j< col;j++)            {                if(Rooms[i,j] = =0) {DFS (rooms, I+1, J,row,col,0 ); DFS (rooms, I-1, J,row,col,0 ); DFS (rooms, i,j-1, Row,col,0 ); DFS (rooms, i,j+1, Row,col,0 ); }            }        }        return; }        Private voidDFS (int[,] rooms,intXintYintRowintColintSentinel) {        if(x<0|| x>= row)return; if(y<0|| y>= Col)return; if(Rooms[x,y] <=0)return; if(Rooms[x,y] < sentinel+1)return; Rooms[x,y]=sentinel+1; DFS (rooms, x+1, Y,row,col, Rooms[x,y]); DFS (rooms, x-1, Y,row,col, Rooms[x,y]); DFS (rooms, x, y-1, Row,col, Rooms[x,y]); DFS (rooms, x, y+1, Row,col, Rooms[x,y]); }

286. Walls and Gates