# Codeforces 346C Number Transformation II 构造

= = 990+ms卡过

#include<stdio.h>
#include<iostream>
#include<string.h>
#include<algorithm>
#include<vector>
#include<set>
using namespace std;
#define N 100010
#define L(x) (x<<1)
#define R(x) (x<<1|1)
#define ll int
ll n,m,k,a,b;
ll x[N];
bool cmp(ll z,ll y){return z>y;}
set<int>myset;
set<int>::iterator p;
int main(){
ll i,j;
while(cin>>n){
myset.clear();
for(i=1;i<=n;i++)scanf("%d",&j),myset.insert(j);
cin>>a>>b;
if(a==b){puts("0");continue;}
n = myset.size();
i = 1;
for(p = myset.begin(); p!=myset.end(); p++,i++)x[i] = *p;
sort(x+1,x+1+n,cmp);
ll step = 0;
ll l = 1;
while(x[l]>a && l<=n)l++;
while(x[l]>(a>>1) && (a-x[l])>(a-b))l++;
if(l>n){cout<<a-b<<endl;continue;}

while(a!=b){
step++;
ll now = 1, cha = a-b;

for(i = l;i<=n;i++)
{
if(now>=x[i])break;
ll tmp = a-((a/x[i])*x[i]);
if(tmp<=now || tmp>cha)continue;
now = tmp;
}
a-=now;
while(x[l]>a&&l<=n)l++;
while(x[l]>(a>>1) && (a-x[l])>cha)l++;
if(l>n)break;
}
cout<<step+a-b<<endl;
}
return 0;
}

posted @ 2016-04-23 18:00  yxwkaifa  阅读(432)  评论(0编辑  收藏  举报