我且为君槌碎黄鹤楼
君亦为吾倒却鹦鹉洲
原地哈希2333。
class Solution {
private:
static int dx[8];
static int dy[8];
inline void check_for_alive(vector<vector<int>> &board, int i, int j) {
int m = board.size(), n = board[0].size();
int alive_cnt = 0, dead_cnt = 0;
for (int a = 0; a < 8; a++) {
int mi = i + dx[a], nj = j + dy[a];
if (0 <= mi && mi < m && 0 <= nj && nj < n) {
if (board[mi][nj] & 1)
alive_cnt++;
}
}
if (board[i][j]) {
if (2 <= alive_cnt && alive_cnt <= 3)
board[i][j] |= 512;
} else {
if (alive_cnt == 3)
board[i][j] |= 512;
}
}
public:
void gameOfLife(vector<vector<int>>& board) {
int m = board.size();
int n = board[0].size();
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) check_for_alive(board, i, j);
}
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
board[i][j] = (board[i][j] >> 9);
}
}
}
};
int Solution::dx[] = {-1, -1, -1, 0, 0, 1, 1, 1};
int Solution::dy[] = {-1, 0, 1, -1, 1, -1, 0, 1};
