求解答289. 生命游戏

[taotie6]

如题

[BerBai]

class Solution {
    public void gameOfLife(int[][] board) {
        int[] neighbors = {0, 1, -1};

        int rows = board.length;
        int cols = board[0].length;

        // 创建复制数组 copyBoard
        int[][] copyBoard = new int[rows][cols];

        // 从原数组复制一份到 copyBoard 中
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                copyBoard[row][col] = board[row][col];
            }
        }

        // 遍历面板每一个格子里的细胞
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {

                // 对于每一个细胞统计其八个相邻位置里的活细胞数量
                int liveNeighbors = 0;

                for (int i = 0; i < 3; i++) {
                    for (int j = 0; j < 3; j++) {

                        if (!(neighbors[i] == 0 && neighbors[j] == 0)) {
                            int r = (row + neighbors[i]);
                            int c = (col + neighbors[j]);

                            // 查看相邻的细胞是否是活细胞
                            if ((r < rows && r >= 0) && (c < cols && c >= 0) && (copyBoard[r][c] == 1)) {
                                liveNeighbors += 1;
                            }
                        }
                    }
                }

                // 规则 1 或规则 3      
                if ((copyBoard[row][col] == 1) && (liveNeighbors < 2 || liveNeighbors > 3)) {
                    board[row][col] = 0;
                }
                // 规则 4
                if (copyBoard[row][col] == 0 && liveNeighbors == 3) {
                    board[row][col] = 1;
                }
            }
        }
    }
}