class Solution {

public:

void gameOfLife(vector<vector<int>>& board) {

if(board.empty()) return;

vector<vector<int>> copyb=board;

int m=board.size();

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

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

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

int val=getNeigh(copyb,i,j);

if(val<2||val>3) board[i][j]=0;

if(copyb[i][j]==0&&val==3) board[i][j]=1;

}

}

}

private:

int getNeigh(vector<vector<int>>& board,int x,int y){

int count=0;

int m=board.size();

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

for(int i=x-1;i<=x+1;++i){

for(int j=y-1;j<=y+1;++j){

if(i<0||j<0||i>=m||j>=n||(i==x&&j==y)) continue;

if(board[i][j]==1){

count++;

}

}

}

return count;

}

};