BZOJ(8) 1053: [HAOI2007]反素数ant

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
int s[20];
long long n,ans,maxn;
int pl[13]={0,2,3,5,7,11,13,17,19,23,29,31,37};
void dfs(long long x,int y,int z){
    if(z==11)    return ;
    if(y>maxn||y==maxn&&x<ans)
        maxn=y,ans=x;
    s[z]=0;
    while(x*pl[z]<=n&&s[z]<s[z-1]){
        s[z]++;
        x*=pl[z];
        dfs(x,y*(s[z]+1),z+1);
    }
}
int main(){
    cin>>n;
    s[0]=1000000;
    dfs(1,1,1);
    cout<<ans;
}