HDU 3844 Mining Your Own Business

 1 #include <cstdio>
 2 #include <iostream>
 3 #include <cstring>
 4 #include <algorithm>
 5 #pragma comment(linker, "/STACK:102400000,102400000")
 6 using namespace std;
 7 typedef long long LL;
 8 const int maxn = 50010;
 9 struct arc {
10     int to,next;
11     arc(int x = 0,int y = -1) {
12         to = x;
13         next = y;
14     }
15 } e[1000010];
16 int head[maxn],dfn[maxn],low[maxn],idx,tot,cn;
17 bool cut[maxn];
18 void add(int u,int v) {
19     e[tot] = arc(v,head[u]);
20     head[u] = tot++;
21     e[tot] = arc(u,head[v]);
22     head[v] = tot++;
23 }
24 void tarjan(int u,int fa) {
25     dfn[u] = low[u] = ++idx;
26     int son = 0;
27     for(int i = head[u]; ~i; i = e[i].next) {
28         if(e[i].to == fa) continue;
29         if(!dfn[e[i].to]) {
30             tarjan(e[i].to,u);
31             son++;
32             low[u] = min(low[u],low[e[i].to]);
33             if(fa != -1 && low[e[i].to] >= dfn[u] || fa == -1 && son > 1) {
34                 cut[u] = true;
35                 cn++;
36             }
37         } else low[u] = min(low[u],dfn[e[i].to]);
38     }
39 }
40 bool vis[maxn];
41 int cnt,n,m,cao;
42 bool fk[maxn];
43 void dfs(int u,int fa) {
44     vis[u] = true;
45     cnt++;
46     for(int i = head[u]; ~i; i = e[i].next) {
47         if(e[i].to == fa) continue;
48         if(cut[e[i].to]) {
49             if(!fk[e[i].to]) {
50                 cao++;
51                 fk[e[i].to] = true;
52             }
53             continue;
54         }
55         if(vis[e[i].to]) continue;
56         dfs(e[i].to,fa);
57     }
58 }
59 int main() {
60     int u,v,cs = 1;
61     while(scanf("%d",&m),m) {
62         memset(head,-1,sizeof head);
63         for(int i = tot = n = idx = cn = 0; i < m; ++i) {
64             scanf("%d%d",&u,&v);
65             add(u,v);
66             n = max(n,max(u,v));
67         }
68         memset(dfn,0,sizeof dfn);
69         memset(cut,false,sizeof cut);
70         for(int i = 1; i <= n; ++i)
71             if(!dfn[i]) tarjan(i,-1);
72         LL ret = 1;
73         if(!cn) printf("Case %d: %d %I64d\n",cs++,2,(LL)n*(n-1)/2);
74         else {
75             memset(vis,false,sizeof vis);
76             int ri = 0;
77             for(int i = 1; i <= n; ++i) {
78                 if(cut[i] || vis[i]) continue;
79                 cnt = cao = 0;
80                 memset(fk,false,sizeof fk);
81                 dfs(i,-1);
82                 if(cao < 2 && cnt) {ri++; ret *= cnt;}
83             }
84             printf("Case %d: %d %I64d\n",cs++,ri,ret);
85         }
86     }
87     return 0;
88 }