"Min cut" "Dinic" "Strong Unicom" bzoj1797 [ahoi2009]mincut min. cut

Conclusion:

Satisfies the condition one: when the beginning and the end point of an edge is not in a strong unicom component of the residual quantity network. and full stream.

Satisfies the condition two: when the beginning and the end point of an edge are in the strong unicom component of S and T respectively. and full stream. 、

Online a lot of.

1#include <cstdio>2#include <cstring>3#include <vector>4#include <algorithm>5#include <queue>6 using namespacestd;7 #defineINF 21474836478 #defineMAXN 40119 #defineMAXM 120101Ten intV[MAXM],CAP[MAXM],EN,FIRST[MAXN],NEXT[MAXM]; One intd[maxn],cur[maxn],cmp[maxn],sum; A BOOLVIS[MAXN]; -queue<int>Q; -vector<int>vs; the intn,m,s,t,a,b,c; - voidInit_dinic () {memset (first,-1,sizeof(first)); en=0;} - voidAddedge (Const int&u,Const int&v,Const int&W) -{v[en]=v; cap[en]=w; next[en]=first[u]; first[u]=en++; +V[en]=u; NEXT[EN]=FIRST[V]; first[v]=en++;} - BOOLBFS () + { Amemset (d,-1,sizeof(d)); Q.push (S); d[s]=0; at      while(!q.empty ()) -       { -         intu=Q.front (); Q.pop (); -          for(inti=first[u];i!=-1; i=Next[i]) -           if(d[v[i]]==-1&&Cap[i]) -             { ind[v[i]]=d[u]+1; - Q.push (V[i]); to             } +       } -     returnd[t]!=-1; the } * intDfsintUinta) $ {Panax Notoginseng     if(u==t | |!a)returnA; -     intflow=0, F; the      for(int&i=cur[u];i!=-1; i=Next[i]) +       if(d[u]+1==d[v[i] && (f=Dfs (v[i],min (a,cap[i )))) A         { theCap[i]-=f; cap[i^1]+=F; +Flow+=f; A-=f;if(!a) Break; -         } $     if(! Flow) d[u]=-1; $     returnFlow; - } - voidMax_flow () the { -      while(BFS ())Wuyi       { thememcpy (Cur,first, (n+5)*sizeof(int)); -          while(Dfs (S,inf)); Wu       } - } About voidDfsintU) $ { -vis[u]=1; -      for(inti=first[u];i!=-1; I=next[i])if(cap[i]&& (!Vis[v[i])) DFS (V[i]); - Vs.push_back (U); A } + voidDFS2 (intU) the { -cmp[u]=sum; $      for(inti=first[u];i!=-1; I=next[i])if(cap[i^1]&& (!Cmp[v[i])) DFS2 (V[i]); the } the voidSCC () the { the      for(intI=1; i<=n;i++)if(!Vis[i]) DFS (i); -vector<int>::iterator It=vs.end (); --it; in      for(;; --it) the       { the         if(!cmp[*it]) {++sum; DFS2 (*it);} About         if(It==vs.begin ()) Break; the       } the } the intMain () + { -scanf"%d%d%d%d",&n,&m,&s,&T); Init_dinic (); the      for(; m;--m)Bayi       { thescanf"%d%d%d",&a,&b,&C); the Addedge (a,b,c); -       } - Max_flow (); SCC (); the      for(intI=0; i<en;i+=2) theprintf"%d%d\n", (!cap[i]) &&cmp[v[i+1]]!=cmp[v[i]], (!cap[i]) &&cmp[v[i+1]]==cmp[s]&&cmp[v[i]]==cmp[t]); the     return 0; the}

"Min cut" "Dinic" "Strong Unicom" bzoj1797 [ahoi2009]mincut min. cut