CF1474B - Different Divisors

Title:

Given d, it is required to output a number x, x has at least 4 factors, and the difference between any two factors of x must be greater than or equal to d.

answer:

Play with your hands, x must be the product of 2 prime numbers. The first factor a is the smallest prime number >=1+x, and the second factor b is the smallest prime number >=1+a.

AC code:

#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define lep(i,a,b) for(int i=(a);i>=(b);i--) 
#define pii pair<int,int>
#define pll pair<long long,long long>
#define mp make_pair
#define All(x) x.begin(),x.end() 
#define ms(a,b) memset(a,b,sizeof(a)) 
#define INF 0x3f3f3f3f
#define INFF 0x3f3f3f3f3f3f3f3f
#define multi int T;scanf("%d",&T);while(T--) 
using namespace std;
typedef long long ll;
typedef double db;
const int N=1e6+5;
const int mod=1e9+7;
const db eps=1e-6;                                                                            
const db pi=acos(-1.0);
int n,m;
int prime[N],cnt;//素数筛¸ 
bool vis[N];
void pr(int n)
{
	ms(vis,0);
	for(int i=2;i<=n;i++)
	{
		if(!vis[i])
		{
			prime[cnt++]=i;
		}
		for(int j=0;j<cnt&&prime[j]<=n/i;j++)
		{
			vis[prime[j]*i]=1;
			if(i%prime[j]==0)
			{
				break;
			}
		}	
	}
}

int main(){
    #ifndef ONLINE_JUDGE
    freopen("D:\\work\\data.in","r",stdin);
    #endif
    pr(1000000);
    multi{
        cin>>n;
        int posa=lower_bound(prime,prime+cnt,1+n)-prime,posb=lower_bound(prime,prime+cnt,prime[posa]+n)-prime;
        cout<<prime[posa]*prime[posb]<<endl;
    }
}

 

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Origin blog.csdn.net/Luowaterbi/article/details/112912169