leetcode 289生命游戏

 

class Solution {
public:
    vector<vector<int>> dirs={{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1},{-1,0},{-1,1}};
    void gameOfLife(vector<vector<int>>& board) {
        //time O(2*9*m*n)
        int r=board.size();
        if(r==0) return;
        int c=board[0].size();
        if(c==0) return;
        vector<vector<int>> cur(r,vector(c,0));
        
        for(int i=0;i<r;i++){
            for(int j=0;j<c;j++){
                for(auto dir:dirs){
                    int x=i+dir[0],y=j+dir[1];
                    if(x<0 || x>=r || y<0 || y>=c) continue;
                    cur[i][j]+=board[x][y];
                }
            }
        }
        for(int i=0;i<r;i++){
            for(int j=0;j<c;j++){

                if( cur[i][j]==3 || board[i][j]==1 && cur[i][j]==2 )
                    board[i][j]=1;
                else
                    board[i][j]=0;
            }

        }
    }
};