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| class Solution {
private final int[][] DIRECTIONS = new int[][] { { -1, -1 }, { -1, 0 }, { -1, 1 }, { 0, 1 }, { 1, 1 }, { 1, 0 },
{ 1, -1 }, { 0, -1 } };
public void gameOfLife(int[][] board) {
for (int row = 0; row < board.length; row++) {
for (int col = 0; col < board[0].length; col++) {
int liveNeighbors = countLiveNeighbors(board, row, col);
if (board[row][col] == 1) {
board[row][col] = liveNeighbors < 2 ? -1 : liveNeighbors <= 3 ? 1 : -1;
} else {
board[row][col] = liveNeighbors == 3 ? -2 : 0;
}
}
}
for (int row = 0; row < board.length; row++) {
for (int col = 0; col < board[0].length; col++) {
if (board[row][col] == -1) {
board[row][col] = 0;
} else if (board[row][col] == -2) {
board[row][col] = 1;
}
}
}
}
private int countLiveNeighbors(int[][] board, int row, int col) {
int ans = 0;
for (int[] direction : DIRECTIONS) {
int newRow = row + direction[0];
int newCol = col + direction[1];
if (!isOutOfBound(board, newRow, newCol) && Math.abs(board[newRow][newCol]) == 1) {
ans += 1;
}
}
return ans;
}
private boolean isOutOfBound(int[][] board, int row, int col) {
return row < 0 || row >= board.length || col < 0 || col >= board[0].length;
}
}
|
