1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
| #include<bits/stdc++.h>
using namespace std;
#define Max 100000
vector<int> graph[Max];
int parent[Max];
int low[Max];
int d[Max];
int visited[Max];
bool isArticulationPoint[Max];
int Time = 0;
void dfs(int u, int root)
{
Time = Time + 1;
visited[u] = Time;
d[u] = low[u] = Time;
int noOfChildren = 0;
for(int i = 0; i <graph[u].size(); i++){
int v = graph[u][i];
if(v == parent[u])continue;
parent[v] = u;
if(visited[v]) low[u] = min(low[u], d[v]);
else{
noOfChildren = noOfChildren + 1;
dfs(v, root);
low[u] = min(low[u], low[v]);
if(low[v] >= d[u] and u != root)isArticulationPoint[u] = true;
}
}
if(u == root and noOfChildren > 1)isArticulationPoint[u] = true;
}
int main()
{
int n,x,y;
char c;
while(cin >> n && n)
{
Time = 0;
for(int t = 0; t <= n; t++){
graph[t].clear();
parent[t]= low[t] = d[t] = visited[t] = 0;
isArticulationPoint[t] = false;
}
while(scanf("%d", &x) == 1 && x)
{
while(scanf("%d%c", &y, &c) == 2)
{
graph[x].push_back(y);
graph[y].push_back(x);
if(c == '\n') break;
}
}
dfs(1, 1);
cout << count(isArticulationPoint+1, isArticulationPoint+n+1, true)<<endl;
}
return 0;
}
|
No comments:
Post a Comment