【BZOJ2118】墨墨的等式（同余最短路）

题意：

思路：From https://www.cnblogs.com/GavinZheng/p/11709153.html#4421510

写的1e9，int范围的

 #include<bits/stdc++.h>
 using namespace std;
 typedef long long ll;
 typedef unsigned int uint;
 typedef unsigned long long ull;
 typedef long double ld;
 typedef pair<int,int> PII;
 typedef pair<ll,ll> Pll;
 typedef vector<int> VI;
 typedef vector<PII> VII;
 typedef pair<ll,ll>P;
 #define N  500010
 #define M  6000010
 #define INF 1e9
 #define fi first
 #define se second
 #define MP make_pair
 #define pb push_back
 #define pi acos(-1)
 #define mem(a,b) memset(a,b,sizeof(a))
 #define rep(i,a,b) for(int i=(int)a;i<=(int)b;i++)
 #define per(i,a,b) for(int i=(int)a;i>=(int)b;i--)
 #define lowbit(x) x&(-x)
 #define Rand (rand()*(1<<16)+rand())
 #define id(x) ((x)<=B?(x):m-n/(x)+1)
 #define ls p<<1
 #define rs p<<1|1
 #define fors(i) for(auto i:e[x]) if(i!=p)

 const int MOD=1e8+,inv2=(MOD+)/;
       int p=1e4+;
       double eps=1e-;
       int dx[]={-,,,};
       int dy[]={,,-,};

 ll dis[N];
 int head[N],vet[M],nxt[M],len[M],a[N],vis[N],mn,n,tot;

 int read()
 {
    int v=,f=;
    char c=getchar();
    while(c<||<c) {if(c=='-') f=-; c=getchar();}
    while(<=c&&c<=) v=(v<<)+v+v+c-,c=getchar();
    return v*f;
 }

 ll readll()
 {
    ll v=,f=;
    char c=getchar();
    while(c<||<c) {if(c=='-') f=-; c=getchar();}
    while(<=c&&c<=) v=(v<<)+v+v+c-,c=getchar();
    return v*f;
 }

 void add(int a,int b,int c)
 {
     nxt[++tot]=head[a];
     vet[tot]=b;
     len[tot]=c;
     head[a]=tot;
 }

 void build()
 {
     rep(i,,mn-) head[i]=;
     tot=;
     rep(i,,mn-)
      rep(j,,n) add(i,(i+a[j])%mn,a[j]);
 }

 void dijk()
 {
     priority_queue<pair<ll,int> >q;
     mem(vis,);
     mem(dis,0x3f);
     q.push(MP(,)); dis[]=;
     while(!q.empty())
     {
         int u=q.top().se;
         q.pop();
         if(vis[u]) continue;
         vis[u]=;
         int e=head[u];
         while(e)
         {
             int v=vet[e];
             if(dis[u]+len[e]<dis[v])
             {
                 dis[v]=dis[u]+len[e];
                 q.push(MP(-dis[v],v));
             }
             e=nxt[e];
         }
     }
 }

 int main()
 {
     n=read();
     ll L=readll(),R=readll();
     L--;
     mn=INF;
     int flag=;
     rep(i,,n)
     {
         a[i]=read();
         if(a[i])
         {
             mn=min(mn,a[i]);
             flag=;
         }
     }
     if(mn==INF)
     {
         printf("0\n");
         return ;
     }
     build();
     dijk();
     if(flag) dis[]=;
      else dis[]=mn;
     ll ans=;
     rep(i,,mn-)
     {
         if(R>=dis[i]) ans+=((R-dis[i])/mn)+;
         if(L>=dis[i]) ans-=((L-dis[i])/mn)+;
     }
     printf("%lld\n",ans);
     return ;
 }