这题有一个潜藏的性质
直接统计的因数,然后组合搞一下即可
记得这题要开(反正我开的int128)
//2*31*1847 //Copyright (c) 2019 by xiao_mmQF. All Rights Reserved. #include<bits/stdc++.h> #define int __int128 #pragma GCC optimize(3) #define inl inline #define reg register #define db long double #define INF 0x3f3f3f3f3f3f3f3f using namespace std; inl int read(){ int x=0,f=0; char ch=0; while(!isdigit(ch))f|=(ch=='-'),ch=getchar(); while(isdigit(ch))(x*=10)+=(ch^48),ch=getchar(); return f?-x:x; } inl void Ot(reg int x) { if(x<0)putchar('-'),x=-x; if(x>=10)Ot(x/10); putchar(x%10+'0'); } inl void Print(reg int x,char til='\n'){Ot(x);putchar(til);} inl int Max(reg int x,reg int y){return x>y?x:y;} inl int Min(reg int x,reg int y){return x<y?x:y;} inl int Abs(reg int x){return x<0?-x:x;} int n; int a,b,c,d,e,all,f; int one,ans; signed main() { n=read(); for(reg int i=1;i<=n;i++) { int k=read(); if(k==1)one++; if(k==2)a++; if(k==31)b++; if(k==1847)c++; if(k==31*1847)e++; if(k==31*2)d++; if(k==2*31*1847)all++; if(k==2*1847)f++; } if(all)ans+=one*all,ans+=all; if(d&&c)ans+=one*d*c,ans+=d*c; if(a&&b&&c)ans+=a*b*c,ans+=one*a*b*c; if(a&&e)ans+=a*e,ans+=one*a*e; if(b&&f)ans+=b*f,ans+=one*b*f; Print(ans); return 0 ; }