gameoflife.cpp

class Solution {
public:
    void gameOfLife(vector<vector<int>>& board) {
        int m = board.size();
        int n = m ? board[0].size() : 0;
        for(int i = 0;i<m;i++)
        {
            for(int j = 0;j<n;j++)
            {
                int count = 0;
                for(int I=max(i-1,0);I<min(i+2,m);I++)
                {
                    for(int J=max(j-1,0);J<min(j+2,n);J++)
                    {
                        count += board[I][J] & 1;
                    }
                }
                if(count==3||count-board[i][j]==3)
                {
                    board[i][j] |= 2;
                }
            }

        }
        for(int i = 0;i<m;i++)
        {
            for(int j = 0;j<n;j++)
            {
                board[i][j] = board[i][j] >> 1;
            }
        }
    }
};