题目描述
方格填数
全排列+检查
代码实现package com.atguigu.TEST;
import static java.lang.Math.abs;
class Main{
static int a[]={0,1,2,3,4,5,6,7,8,9};
static int ans;
public static boolean check(){
if (abs(a[0] - a[1]) == 1 || abs(a[0] - a[3]) == 1 || abs(a[0] - a[4]) == 1 || abs(a[0] - a[5]) == 1 ||
abs(a[1] - a[2]) == 1 || abs(a[1] - a[4]) == 1 || abs(a[1] - a[5]) == 1 || abs(a[1] - a[6]) == 1 ||
abs(a[2] - a[5]) == 1 || abs(a[2] - a[6]) == 1 ||
abs(a[3] - a[4]) == 1 || abs(a[3] - a[7]) == 1 || abs(a[3] - a[8]) == 1 ||
abs(a[4] - a[5]) == 1 || abs(a[4] - a[7]) == 1 || abs(a[4] - a[8]) == 1 || abs(a[4] - a[9]) == 1 ||
abs(a[5] - a[6]) == 1 || abs(a[5] - a[8]) == 1 || abs(a[5] - a[9]) == 1 ||
abs(a[6] - a[9]) == 1 ||
abs(a[7] - a[8]) == 1 ||
abs(a[8] - a[9]) == 1)
return false;
return true;
}
public static void f(int k){
if(k==10){//一种排列已经生成
if(check())
ans++;
return;
}
//从k往后每个数字都可以放在k位
for (int i = k; i < 10; i++) {
int temp=a[i];
a[i]=a[k];
a[k]=temp;
f(k+1);
temp=a[i];
a[i]=a[k];
a[k]=temp;
}
}
public static void main(String[] args) {
f(0);
System.out.println(ans);
}
}
1580
