题解 | #疯牛病I#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param pasture int整型二维数组
     * @param k int整型
     * @return int整型
     */
    public int healthyCows (int[][] pasture, int k) {
        if(k == 0){  //k为0时退出递归并统计正常牛数目
            int flag = 0;
            for (int[] i : pasture){
                for (int j : i){
                    if(j == 1){
                        flag++;
                    }
                }
            }
            return flag;
        }
	  	//正常遍历并将即将变为疯牛的牛先标记为3而不是2，避免干扰循环
        for (int i = 0; i < pasture.length;i++){
            for (int j = 0;j< pasture[i].length; j++){
                if(pasture[i][j]==2){
                    if(i-1>=0&&pasture[i-1][j]==1){
                        pasture[i-1][j]=3;
                    }
                    if(i+1<pasture.length&&pasture[i+1][j]==1){
                        pasture[i+1][j]=3;
                    }
                    if(j-1>=0&&pasture[i][j-1]==1){
                        pasture[i][j-1]=3;
                    }
                    if(j+1<pasture[i].length&&pasture[i][j+1]==1){
                        pasture[i][j+1]=3;
                    }
                }
            }
        }
	  	//牛牛变异为2
        for (int i = 0; i < pasture.length;i++){
            for (int j = 0;j< pasture[i].length; j++){
                if(pasture[i][j] == 3){
                    pasture[i][j]=2;
                }
            }
        }
        return healthyCows(pasture, k-1);
        // write code here
    }
}