生命游戏

题目描述：力扣

思路：使用了BFS，看官方解答并没有用到算法，而是复制了数组，是复制的数组保持不变，判断的时候也是利用复制的数组判断是否改变。

class Solution {
    public void gameOfLife(int[][] board) {
        int row = board.length;
        int col = board[0].length;
        int[][] state = new int[row][col];
        for(int i = 0 ; i < row; i++){
            for(int j = 0 ; j < col; j++){
                state[i][j]=0;
            }
        }
        for(int i = 0 ; i < row; i++){
            for(int j = 0 ; j < col; j++){
                bfs(board, state,i,j);
            }
        }
    }

    public void bfs(int[][] board, int[][] state, int i, int j){
        int row = board.length;
        int col = board[0].length;
        if(i<0 || i>=row || j < 0 || j >=col){
            return;
        }
        if(state[i][j]==1)
            return;
        state[i][j]=1;
        int sum = sumaround(board, i-1, j-1)+sumaround(board, i-1, j)+sumaround(board, i-1, j+1)+sumaround(board, i, j-1)+sumaround(board, i, j+1)+ sumaround(board, i+1, j-1)+sumaround(board, i+1, j)+sumaround(board, i+1, j+1);
        if((board[i][j]==0 && sum==3)||(board[i][j]==1 && (sum<2 || sum >3))){
            bfs(board, state , i-1, j-1);
            bfs(board, state , i-1, j);
            bfs(board, state , i-1, j+1);
            bfs(board, state , i, j-1);
            bfs(board, state , i, j+1);
            bfs(board, state , i+1, j-1);
            bfs(board, state , i+1, j);
            bfs(board, state , i+1, j+1);
            if(board[i][j]==0){
                board[i][j]=1;
            }
            else{
                board[i][j]=0;
            }
        }
        else{
            return;
        }

    }

    public int sumaround(int[][] board, int i, int j){
        int row = board.length;
        int col = board[0].length;
        if(i<0 || i>=row || j < 0 || j >=col){
            return 0;
        }
        else{
            return board[i][j];
        }
    }
}