HDU 3749 Financial Crisis

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 const int maxn = 5010;
 4 struct arc {
 5     int u,v;
 6     arc(int x = 0,int y = 0) {
 7         u = x;
 8         v = y;
 9     }
10 };
11 int low[maxn],dfn[maxn],bccno[maxn],clk,bcc_cnt;
12 vector<int>g[maxn],bcc[maxn],belong[maxn];
13 stack<arc>stk;
14 void tarjan(int u,int fa) {
15     dfn[u] = low[u] = ++clk;
16     bool flag = false;
17     for(int i = g[u].size()-1; i >= 0; --i) {
18         if(!flag && g[u][i] == fa) {
19             flag = true;
20             continue;
21         }
22         if(!dfn[g[u][i]]) {
23             stk.push(arc(u,g[u][i]));
24             tarjan(g[u][i],u);
25             low[u] = min(low[u],low[g[u][i]]);
26             if(low[g[u][i]] >= dfn[u]) {
27                 bcc[++bcc_cnt].clear();
28                 while(true) {
29                     arc e = stk.top();
30                     stk.pop();
31                     if(bccno[e.u] != bcc_cnt) {
32                         bccno[e.u] = bcc_cnt;
33                         bcc[bcc_cnt].push_back(e.u);
34                         belong[e.u].push_back(bcc_cnt);
35                     }
36                     if(bccno[e.v] != bcc_cnt) {
37                         bccno[e.v] = bcc_cnt;
38                         bcc[bcc_cnt].push_back(e.v);
39                         belong[e.v].push_back(bcc_cnt);
40                     }
41                     if(e.u == u && e.v == g[u][i]) break;
42                 }
43             }
44         } else if(dfn[g[u][i]] < dfn[u]) {
45             stk.push(arc(u,g[u][i]));
46             low[u] = min(low[u],dfn[g[u][i]]);
47         }
48     }
49 }
50 int uf[maxn];
51 int Find(int x) {
52     if(x != uf[x]) uf[x] = Find(uf[x]);
53     return uf[x];
54 }
55 void init() {
56     for(int i = clk = bcc_cnt = 0; i < maxn; ++i) {
57         bccno[i] = dfn[i] = 0;
58         g[i].clear();
59         belong[i].clear();
60         uf[i] = i;
61     }
62     while(!stk.empty()) stk.pop();
63 }
64 int main() {
65     int n,m,q,u,v,cs = 1;
66     while(scanf("%d%d%d",&n,&m,&q),n||m||q) {
67         init();
68         for(int i = 0; i < m; ++i) {
69             scanf("%d%d",&u,&v);
70             g[u].push_back(v);
71             g[v].push_back(u);
72             u = Find(u);
73             v = Find(v);
74             if(u != v) uf[v] = u;
75         }
76         for(int i = 0; i < n; ++i)
77             if(!dfn[i]) tarjan(i,-1);
78         printf("Case %d:\n",cs++);
79         while(q--) {
80             scanf("%d%d",&u,&v);
81             if(Find(u) != Find(v)) puts("zero");
82             else {
83                 bool flag = false;
84                 for(auto &a:belong[u])
85                     for(auto &b:belong[v])
86                         if(a == b && bcc[a].size() > 2)
87                             flag = true;
88                 puts(flag?"two or more":"one");
89             }
90         }
91     }
92     return 0;
93 }