HDU 2710 Max Factor 数论（水

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <vector>
#include <iomanip>
#include <math.h>
#include <map>
using namespace std;
#define FIN     freopen("input.txt","r",stdin);
#define INF     0x3f3f3f3f
#define lson    l,m,rt<<1
#define rson    m+1,r,rt<<1|1
typedef long long LL;

const int MAXN=20005;

int p[MAXN];

int main()
{
    //FIN
    p[1]=1;
    int cou=0;
    for(int i=2; i<=20005; i++)
    {
        if(p[i]==0)
        {
            cou++;
            for(int j=i; j<=20005; j=j+i)
            {
                p[j]=cou;
            }
        }
    }
    int n;
    while(~scanf("%d",&n))
    {
        int ans=0,pos;
        int x;
        for(int i=1;i<=n;i++){
            scanf("%d",&x);
            if(p[x]>ans)  {ans=p[x];pos=x;}
        }
        printf("%d\n",pos);

    }

}