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
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
#include <cstring>
#include <string>
#include <unordered_map>
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define N 1000
#define T 999000
using namespace std;
struct
{
int v, next;
} E[T];
unordered_map<string, int> M;
int adj[N];
int visited[N], low[N], step;
int component;
bool in_stack[N];
int Stack[N], top;
void DFS(int u)
{
visited[u] = low[u] = ++step;
Stack[top++] = u;
in_stack[u] = true;
for (int i = adj[u]; i != -1; i = E[i].next)
{
int v = E[i].v;
if (!visited[v])
DFS(v);
if (in_stack[v])
low[u] = MIN(low[u], low[v]);
}
if (visited[u] == low[u])
{
++component;
while (true)
{
int v = Stack[--top];
in_stack[v] = false;
if (v == u)
return;
}
}
}
int main()
{
int P, t;
char str[30];
while (scanf("%d%d", &P, &t) && (P || t))
{
getchar();
for (int i = 0; i < P; ++i)
{
fgets(str, 30, stdin);
M[string(str)] = i;
}
memset(adj, -1, sizeof adj);
int idx = 0;
for (int i = 0; i < t; ++i)
{
int u, v;
fgets(str, 30, stdin);
u = M[string(str)];
fgets(str, 30, stdin);
v = M[string(str)];
E[idx] = (edge){v, adj[u]};
adj[u] = idx++;
}
for (int i = 0; i < P; ++i)
if (!visited[i])
DFS(i);
printf("%dn", component);
top = component = step = 0;
memset(visited, 0, sizeof visited);
memset(low, 0, sizeof low);
}
return 0;
}
|
近期评论