【BZOJ】【3850】ZCC Loves Codefires

 1 /**************************************************************
 2     Problem: 3850
 3     User: ProgrammingApe
 4     Language: C++
 5     Result: Accepted
 6     Time:64 ms
 7     Memory:2052 kb
 8 ****************************************************************/
 9  
10 //BZOJ 3850
11 #include<cstdio>
12 #include<cstring>
13 #include<cstdlib>
14 #include<iostream>
15 #include<algorithm>
16 #define rep(i,n) for(int i=0;i<n;++i)
17 #define F(i,j,n) for(int i=j;i<=n;++i)
18 #define D(i,j,n) for(int i=j;i>=n;--i)
19 using namespace std;
20 const int N=100086;
21 typedef long long LL;
22 struct node{
23     int t,k;
24     bool operator < (const node& b) const {
25         return t*k+(t+b.t)*b.k < b.t*b.k+(t+b.t)*k;
26     }
27 }a[N];
28  
29 int main(){
30 //  freopen("input.txt","r",stdin);
31     int n;
32     scanf("%d",&n);
33     F(i,1,n) scanf("%d",&a[i].t);
34     F(i,1,n) scanf("%d",&a[i].k);
35     sort(a+1,a+n+1);
36     LL time=0;
37     LL ans=0;
38     F(i,1,n){
39         time+=a[i].t;
40         ans+=(LL)a[i].k*time;
41     }
42     printf("%lld\n",ans);
43     return 0;
44 }