计蒜客 贝壳找房函数最值（好题，巧妙排序）

 1 #include<bits/stdc++.h>
 2 #define lc(a) (a<<1)
 3 #define rc(a) (a<<1|1)
 4 #define MID(a,b) ((a+b)>>1)
 5 #define fin(name)  freopen(name,"r",stdin)
 6 #define fout(name) freopen(name,"w",stdout)
 7 #define clr(arr,val) memset(arr,val,sizeof(arr))
 8 #define _for(i,start,end) for(int i=start;i<=end;i++)
 9 #define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
10 using namespace std;
11 typedef long long LL;
12 const int N=1e5+5;
13 const int INF=0x3f3f3f3f;
14 const double eps=1e-10;
15 
16 struct node{
17     int a,b;
18 }p[N];
19 
20 bool cmp(node x,node y){
21     return x.a*y.b+x.b>y.a*x.b+y.b;
22 }
23 
24 int main(){
25     FAST_IO;
26     int T;
27     cin>>T;
28     while(T--){
29         int n,x;
30         cin>>n>>x;
31         for(int i=1;i<=n;i++){
32             cin>>p[i].a;
33         }
34         for(int i=1;i<=n;i++){
35             cin>>p[i].b;
36         }
37         sort(p+1,p+1+n,cmp);
38         int ans=0,tmp=1;
39         for(int i=1;i<=n;i++){
40             ans=(ans+tmp*p[i].b)%10;
41             tmp=tmp*p[i].a%10;
42         }
43         ans=(ans+tmp*x)%10;
44         cout<<ans<<endl;
45     }
46     return 0;
47 }