Poj 1904 King's Quest strong connected components

Topic Links:

http://poj.org/problem?id=1904

Test instructions

There are n princes and N princesses, the Prince can only marry his favorite princess (a prince may have a number of favorite princess), has now given a perfect match, ask each Prince can take which princess, and guarantee to take a princess, the overall still exist perfect match.

Exercises

1. Build the map:

If Prince U is right for Princess V, then one side u->v. In the perfect match given by the example, if Prince U marries Princess V, even a side v->u.

2, to find strong connected components:

If the prince and his beloved princess belong to the same strong connecting component, then the Prince can marry the princess.

1#include <iostream>2#include <algorithm>3#include <cstdio>4#include <stack>5#include <vector>6#include <cstring>7 using namespacestd;8 9 Const intmaxn=4444;Ten  One intN; A  - structedge{ -     intV,ne; theEdge (intVintne): V (v), NE (NE) {} - Edge () {} -}egs[201010+MAXN]; -  + intHead[maxn],tot; -  + voidAddedge (intUintv) { Aegs[tot]=Edge (V,head[u]); athead[u]=tot++; - } -  - intpre[maxn],lowlink[maxn],sccno[maxn],dfs_clock,scc_cnt; -stack<int>S; - //read in write optimization in intScan () { -     intret=0, flag=0;Charch; to     if((Ch=getchar ()) = ='-') flag=1; +     Else if(ch>='0'&&ch<='9') ret=ch-'0'; -      while((Ch=getchar ()) >='0'&&ch<='9') ret=ret*Ten+ch-'0'; the     returnflag?-Ret:ret; * } $ Panax Notoginseng void  out(intx) { -     if(x>9) out(x/Ten); thePutchar (%Ten+'0'); + } A //Strong Connectivity the voidDfsintu) { +pre[u]=lowlink[u]=++Dfs_clock; - s.push (u); $      for(inti=head[u];i!=-1; i=egs[i].ne) { $edge& e=Egs[i]; -         intv=e.v; -         if(!Pre[v]) { the Dfs (v); -lowlink[u]=min (lowlink[u],lowlink[v]);Wuyi}Else if(!Sccno[v]) { thelowlink[u]=min (lowlink[u],pre[v]); -         } Wu     }  -     if(lowlink[u]==Pre[u]) { Aboutscc_cnt++; $          for(;;) { -             intx=S.top (); S.pop (); -sccno[x]=scc_cnt; -             if(X==u) Break;  A         } +     } the } -  $ voidFIND_SCC (intN) { theDfs_clock=scc_cnt=0; thememset (Sccno,0,sizeof(SCCNO)); thememset (PRE,0,sizeof(pre)); the      for(intI=0; i<n;i++){ -         if(!Pre[i]) DFS (i); in     } the } the //Building Map About voidbuild () { the     intcnt,v; the      for(intI=0; i<n;i++){ theCnt=Scan (); +          while(cnt--){ -V=scan (); v--;  theAddedge (i,v+N);Bayi         } the     } the      for(intI=0; i<n;i++){ -V=scan (); v--; -Addedge (v+n,i); the     } the } the  the voidinit () { -memset (head,-1,sizeof(head)); thetot=0; the } the 94 intans[201010],t; the  the intMain () { the      while(SCANF ("%d", &n) = =1&&N) {98 init (); About build (); -FIND_SCC (2*N);101          for(intI=0; i<n;i++){102t=0;103              for(intj=head[i];j!=-1; j=egs[j].ne) {                104edge& e=Egs[j]; the                 intv=e.v;106                 if(Sccno[i]==sccno[v]) ans[t++]=v;107             }108Sort (ans,ans+t);109              out(t); the              for(intI=0; i<t;i++){111Putchar (' '); the                  out(ans[i]+1-N);113             } thePutchar ('\ n'); the         } the     }117     return 0;118}

Poj 1904 King's Quest strong connected components