bzoj 3876: [Ahoi2014]支线剧情

就是加一个1的下界就好了。

 #include<bits/stdc++.h>
 #define N 100005
 #define LL long long
 #define inf 0x3f3f3f3f
 #define ls tr[x][0]
 #define rs tr[x][1]
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 struct node{
     int c,v,from,to,next;
 }e[N];
 int tot=,ans,from[N],n,m,S,T,head[N],cnt,dis[N],q[N<<];
 bool inq[N];
 void ine(int x, int y, int v, int c)
 {
     e[++tot].to=y; e[tot].next=head[x]; head[x]=tot;
     e[tot].v=v; e[tot].c=c; e[tot].from=x;
 }
 void insert(int x, int y, int c, int v)
 {
     ine(x,y,v,c); ine(y,x,-v,);
 }
 bool spfa()
 {
     for (int i=; i<=n+; i++) dis[i]=inf;
     int l=,r=; q[]=S; dis[S]=; inq[S]=;
     while (l<r)
     {
         int x=q[l++];
         for (int i=head[x];i;i=e[i].next)
             if (dis[e[i].to]>dis[x]+e[i].v && e[i].c)
             {
                 dis[e[i].to]=dis[x]+e[i].v;
                 from[e[i].to]=i;
                 if (!inq[e[i].to])
                 {
                     inq[e[i].to]=;
                     q[r++]=e[i].to;
                 }
             }
         inq[x]=;
     }
     if (dis[T]==inf) return ;
     return ;
 }
 void mcf()
 {
     int x=inf;
     for (int i=from[T];i;i=from[e[i].from]) x=min(x,e[i].c);
     for (int i=from[T];i;i=from[e[i].from]) ans+=x*e[i].v,e[i].c-=x,e[i^].c+=x;
 }
 void fyl()
 {
     while (spfa()) mcf();
 }
 int main()
 {
     n=ra();
     S=n+; T=n+;
     for (int i=; i<=n; i++)
     {
         int cnt=ra();
         insert(i,T,cnt,);
         if (i!=) insert(i,,inf,);
         for (int j=; j<=cnt; j++)
         {
             int x=ra(),v=ra();
             insert(S,x,,v);
             insert(i,x,inf,v);
         }
     }
     fyl();
     cout<<ans;
     return ;
 }