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

int n = (int)board.size();

if(n == 0) return;

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

if(m == 0) return;

int dx[] = {0, -1, -1, -1, 0, 1, 1, 1};

int dy[] = {-1, -1, 0, 1, 1, 1, 0, -1};

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

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

int liveNeighs = 0;

for(int k = 0; k < sizeof(dx) / sizeof(dx[0]); ++k) {

int x = i + dx[k];

int y = j + dy[k];

liveNeighs += (x >= 0 and y >= 0 and x < n and y < m and (board[x][y] & 1));

}

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

if(liveNeighs == 2 or liveNeighs == 3) {

board[i][j] |= 3;

}

} else {

if(liveNeighs == 3) {

board[i][j] |= 2;

}

}

}

}

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

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

board[i][j] >>= 1;

}

}

}