D. Arpa and a list of numbers Codeforces Round #432 (Div. 2, based on IndiaHacks Final Round 2017)

http://codeforces.com/contest/851/problem/D

分区间操作

 #include <cstdio>
 #include <cstdlib>
 #include <cmath>
 #include <cstring>
 #include <time.h>
 #include <string>
 #include <set>
 #include <map>
 #include <list>
 #include <stack>
 #include <queue>
 #include <vector>
 #include <bitset>
 #include <ext/rope>
 #include <algorithm>
 #include <iostream>
 using namespace std;
 #define ll long long
 #define minv 1e-6
 #define inf 1e18
 #define pi 3.1415926536
 #define E  2.7182818284
 const ll mod=1e9+;//
 const int maxn=2e6+;

 bool vis[maxn]={};
 ll tot[maxn]={},sum[maxn]={};

 int main()
 {
     int n,x,y,z,i,j,pos;
     ll v,r=inf,a;
     scanf("%d%d%d",&n,&x,&y);
     z=x/y;
     for (i=;i<=n;i++)
     {
         scanf("%lld",&a);
         tot[a]++;
         sum[a]+=a;
     }
     for (i=;i<=2e6;i++)
         tot[i]+=tot[i-],sum[i]+=sum[i-];
     for (i=;i<=1e6;i++)
         if (!vis[i])
         {
             v=;
             //(j-i,j)
             for (j=i;j<=2e6;j+=i)
             {
                 pos=max(j-z,j-i+);//[pos,j]
                 v+= (ll)(tot[pos-]-tot[j-i])*x + ( (ll)(tot[j]-tot[pos-])*j-(ll)(sum[j]-sum[pos-]) )*y;
                 vis[j]=;
             }
             r=min(r,v);
         }
     cout<<r;
     return ;
 }