HDU5778 abs

http://acm.hdu.edu.cn/showproblem.php?pid=5778

思路：只有平方质因子的数，也就是这题所说的   y的质因数分解式中每个质因数均恰好出现2次  满足条件的数很幂集

因此枚举sqrt(x)，前后判断一下sqrt(x)的质因子就可以

可以不判断是不是素数

注意x<4的情况

 // #pragma comment(linker, "/STACK:102c000000,102c000000")
 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <sstream>
 #include <string>
 #include <algorithm>
 #include <list>
 #include <map>
 #include <vector>
 #include <queue>
 #include <stack>
 #include <cmath>
 #include <cstdlib>
 // #include <conio.h>
 using namespace std;
 #define pi acos(-1.0)
 const int N =  + ;
 #define inf 0x7fffffff
 typedef long long  LL;

 void fre() { freopen("in.txt","r",stdin);}

 bool isPrime[N];
 LL primeList[N],primeCount = ;

 LL Fast_power(LL n,LL k,LL mod) {
     if(k == )  return ;
     LL temp = Fast_power(n,k / ,mod);
     temp = (temp * temp) % mod;
     if(k %  == )  temp = (temp * (n % mod)) % mod;
     return temp;
 }

 void Eular_Sieve(LL n) {
     memset(isPrime,true,sizeof(isPrime));
     isPrime[] = false;
     isPrime[] = false;
     for(int i = ; i <= n; i ++) {
         if(isPrime[i]) {
             primeCount ++;
             primeList[primeCount] = i;
         }
         for(int j = ; j <= primeCount; j ++) {
             if(i * primeList[j] > n)    break;
             isPrime[i * primeList[j]] = false;
             if(!(i % primeList[j]))    break;
         }
     }
 }

 int Mr[] = {, , , , , , , , , , , };
 bool Miller_Rabin(LL n) {
     if(n == )           return true;
     else if(n < )       return false;
     if(n %  == )       return false;
     LL u = n - ;
     while(u %  == )   u = u / ;
     int  tempu = u;
     for(int i = ; i < ; i ++) {
         if(Mr[i] >= n)  break;
         u = tempu;
         LL x = Fast_power(Mr[i],u,n);
         while(u < n) {
             LL y = (x % n) * (x % n) % n;
             if(y ==  && x !=  && x != n - )  return false;
             x = y;
             u = u * ;
         }
         if(x != )  return false;
     }
     return true;
 }

 int main() {
     // fre();
     Eular_Sieve();
     int T;
     scanf("%d",&T);
     while(T --) {
         LL  n;
         scanf("%I64d",&n);
         if(n<=){
             printf("%d\n",-n);
             continue;
         }
         LL x = sqrt(n);
         LL y = sqrt(n) + ;
         LL cnt = ,ans = ;
         while() {
             LL xx = x - cnt;
             if(Miller_Rabin(xx)) {
                 ans = n - xx * xx;
                 break;
             } else {
                 LL pp = xx;
                 bool flag = true;
                 for(int i = ; i < primeCount && i * i <= pp; i ++) {
                     int cou = ;
                     while(pp % primeList[i] == )   {
                         pp = pp / primeList[i];
                         cou ++;
                         if(cou>=){
                             break;
                         }
                     }
                     if(cou >= )    {
                         flag = false;
                         break;
                     }
                 }
                 if(flag == true) {
                     ans = n - xx * xx;
                     break;
                 }
             }
             cnt ++;
         }
         cnt = ;
         while() {
             LL yy = y + cnt;
             if(yy * yy - n >= ans)  break;
             if(Miller_Rabin(yy)) {
                 ans = min(ans,yy * yy - n);
                 break;
             } else {
                 LL pp = yy;
                 bool flag = true;
                 for(int i = ; i < primeCount && i * i <= pp; i ++) {
                     int cou = ;
                     while(pp % primeList[i] == )   {
                         pp = pp / primeList[i];
                         cou ++;
                         if(cou>=){
                             break;
                         }
                     }
                     if(cou >= )    {
                         flag = false;
                         break;
                     }
                 }
                 if(flag == true) {
                     ans = min(ans,yy * yy - n);
                     break;
                 }
             }
             cnt ++;
         }
         printf("%I64d\n",ans);
     }
     return ;
 }