重连通分量的求解

 

 

 

  1 // time 32ms
  2 #include <iostream>
  3 #include <cstdio>
  4 #include <cstring>
  5 #include <cmath>
  6 #include <algorithm>
  7 #include <string>
  8 #include <vector>
  9 #include <set>
 10 #include <map>
 11 #include <stack>
 12 #include <queue>
 13 #include <sstream>
 14 #include <iomanip>
 15 using namespace std;
 16 typedef long long LL;
 17 const int INF = 0x4fffffff;
 18 const double EXP = 1e-5;
 19 const int MS = 1005;
 20 const int SIZE = 100005;
 21 
 22 struct edge
 23 {
 24       int u,v;
 25       void output()
 26       {
 27             printf("%d---%d",u,v);
 28       }
 29       int cmp(edge &t)
 30       {
 31             return ((u==t.u&&v==t.v)||(u==t.v&&v==t.u));
 32       }
 33 };
 34 
 35 edge sta[MS];
 36 int top;
 37 int edges[MS][MS];   //  1:连接未入stack，2：连接入过stack
 38 int vis[MS];
 39 int n,m;
 40 int tdfn;
 41 int dfn[MS];
 42 int low[MS];
 43 
 44 void DFS(int u)
 45 {
 46       for(int v=1;v<=n;v++)
 47       {
 48             if(edges[u][v]==1)
 49             {
 50                   edge t;
 51                   t.u=u;t.v=v;sta[++top]=t;
 52                   edges[u][v]=edges[v][u]=2;
 53                   if(!vis[v])
 54                   {
 55                         vis[v]=1;
 56                         dfn[v]=low[v]=++tdfn;
 57                         DFS(v);
 58                         low[u]=min(low[u],low[v]);
 59                         if(low[v]>=dfn[u])
 60                         {
 61                               bool FirstEdge=true;
 62                               while(1)
 63                               {
 64                                     if(top<0)
 65                                           break;
 66                                     if(FirstEdge)
 67                                           FirstEdge=false;
 68                                     else
 69                                           printf(" ");
 70                                     edge t1;
 71                                     t1=sta[top];
 72                                     t1.output();
 73                                     sta[top].u=0;sta[top].v=0;//删除top边
 74                                     top--;
 75                                     if(t1.cmp(t))
 76                                           break;
 77                               }
 78                               printf("\n");
 79                         }
 80                   }
 81                   else
 82                         low[u]=min(low[u],dfn[v]);
 83             }
 84       }
 85 }
 86 
 87 
 88 int main()
 89 {
 90       int i,u,v,number=1;
 91       while(1)
 92       {
 93             scanf("%d%d",&n,&m);
 94             if((n+m)==0)
 95                   break;
 96             memset(edges,0,sizeof(edges));
 97             for(int i=1;i<=m;i++)
 98             {
 99                   scanf("%d%d",&u,&v);
100                   edges[u][v]=edges[v][u]=1;
101             }
102             if(number++>1)
103                   printf("\n");
104             low[1]=dfn[1]=1;
105             tdfn=1;
106             memset(vis,0,sizeof(vis));
107             vis[1]=1;
108             memset(sta,0,sizeof(sta));
109             top=-1;
110             DFS(1);
111       }
112       return 0;
113 }

 

posted @ 2015-04-21 22:35  daydaycode  阅读(92)  评论(0)    收藏  举报