"2-sat (two DFS edition)" bzoj1823-[jsoi2010] Feast

"The main topic"

There are n materials, m judges. Each material can be used to make Manchu or Han Chinese cuisine, and M judges have two kinds of guesses that will satisfy him. Q. Can I meet all the judges ' requirements?

Ideas

Can only do three questions a day, I have been a wreck ... (Ge ping lying. jpg)

Bare 2-sat, first wrote a two times DFS, speed slightly slow ... 24ms?

1#include <iostream>2#include <cstdio>3#include <cstring>4#include <algorithm>5#include <vector>6 using namespacestd;7 Const intmaxn= $+ -;8vector<int>E[MAXN];9vector<int>RE[MAXN];Tenvector<int>vs; One intCMP[MAXN],VIS[MAXN]; A intcnt,n,m; -  - voidAddedge (intUintv) the { - E[u].push_back (v); - re[v].push_back (u); - } +  - voidDfsintu) + { Avis[u]=1; at      for(intI=0; I<e[u].size (); i++) -     { -         intv=E[u][i]; -         if(!Vis[v]) Dfs (v); -     } - vs.push_back (u); in } -  to voidRdfsintUintt) + { -vis[u]=1; thecmp[u]=T; *      for(intI=0; I<re[u].size (); i++) $     {Panax Notoginseng         intv=Re[u][i]; -         if(!Vis[v]) Rdfs (v,t); the     } + } A  the voidInit () + { -      for(intI=0; i<maxn;i++) vector<int>(). Swap (E[i]); $      for(intI=0; i<maxn;i++) vector<int>(). Swap (Re[i]); $scanf"%d%d",&n,&m); -      for(intI=0; i<m;i++) -     { the         Charc1,c2; -         intX,y,fx,fy;Wuyi GetChar (); thescanf"%c%d%c%d",&c1,&x,&c2,&y); -         if(c1=='m') Fx=x+n;Elsefx=x; Wu         if(c2=='m') Fy=y+n;Elsefy=y; -         if(c1=='h') Addedge (X+N,FY);Else if(c1=='m') Addedge (x,fy); About         if(c2=='h') Addedge (Y+N,FX);Else if(c1=='m') Addedge (Y,FX); $     } - } -  - voidSolve () A { +memset (Vis,0,sizeof(Vis)); the      for(intI=1; i<=n;i++)if(!Vis[i]) DFS (i); -memset (Vis,0,sizeof(Vis)), cnt=0; $      for(intI=vs.size ()-1; i>=0; i--) the         if(!vis[vs[i]]) Rdfs (vs[i],++CNT); the } the  the voidGet_ans () - { in      for(intI=1; i<=n;i++) the         if(cmp[i]==cmp[i+N]) the         { AboutPuts" Bad"); the             return; the         } thePuts"Good"); + }  -  the intMain ()Bayi { the     intT; thescanf"%d",&T); -      while(t--) -     { the init (); the solve (); the Get_ans (); the     } -     return 0; the}

"2-sat (two DFS edition)" bzoj1823-[jsoi2010] Feast