JZOJ 4282. 【NOIP2015模拟10.29B组】平方数游戏【暴力】

---

题意：

---

分析：

考场上用模拟退火拿了$76^{\prime }$哈哈哈
愉快打表找规律，只要胆子大，题题都拿下
根据打表，莽撞猜测一下，当$n$足够大的时候，答案奇数是$1$，偶数是$0$
再仔细观察，会有$x^2-(x+1{)}^2-(x+2{)}^2+(x+3{)}^2=4$，那对于相邻的两组，后一组取反下就是$4-4=0$了
就是$x^2-(x+1{)}^2-(x+2{)}^2+(x+3{)}^2-(x+4{)}^2+(x+5{)}^2+(x+6{)}^2-(x+7{)}^2=0$
但对于$n<6$时我们需要自己打表下

---

代码：

#pragma GCC optimize(2)
#include<cstdio>
#include<string>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
#include<cmath>
#include<cstdlib>
#include<ctime>
#define LL long long
#define down 0.993
using namespace std;
inline LL read() {
    LL d=0,f=1;char s=getchar();
    while(s<'0'||s>'9'){if(s=='-')f=-1;s=getchar();}
    while(s>='0'&&s<='9'){d=d*10+s-'0';s=getchar();}
    return d*f;
}
int main()
{
	freopen("five.in","r",stdin);
	freopen("five.out","w",stdout);
	int n=read();
	if(n==1) return !printf("1\n-1");
	if(n==2) return !printf("3\n1 -1");
	if(n==3) return !printf("4/n1 1-1");
	if(n==4) return !printf("2\n1 1 1 -1");
	if(n==5) return !printf("3\n-1 1 1 1 -1");
	if(n%4==1||n%4==2) printf("1\n");
	else printf("0\n");
	if(n%8==6) printf("1 1 -1 1 1 -1 "),n-=6;
	else if(n%8==7) printf("-1 -1 1 -1 1 1 -1 "),n-=7;
	else if(n%8==0) printf("1 -1 -1 1 -1 1 1 -1 "),n-=8;
	else if(n%8==1) printf("1 1 -1 -1 1 -1 1 1 -1 "),n-=9;
	else if(n%8==2) printf("1 -1 -1 -1 1 1 1 -1 1 -1 "),n-=10;
	else if(n%8==3) printf("-1 1 -1 -1 -1 1 1 1 -1 1 -1 "),n-=11;
	else if(n%8==4) printf("-1 1 -1 -1 -1 1 -1 1 -1 1 1 -1 "),n-=12;
	else if(n%8==5) printf("-1 -1 1 -1 -1 1 -1 -1 -1 1 1 1 -1 "),n-=13;
	while(n)
	{
		printf("1 -1 -1 1 -1 1 1 -1 ");
		n-=8;
	}
	return 0;
}

本文地址：https://blog.csdn.net/qq_35786326/article/details/109244789