hdu 5495 LCS (置换群)

Sample Input
2
3
1 2 3
3 2 1
6
1 5 3 2 6 4
3 6 2 4 5 1
Sample Output
2
4
C/C++：
 1 #include <map>
 2 #include <queue>
 3 #include <cmath>
 4 #include <vector>
 5 #include <string>
 6 #include <cstdio>
 7 #include <cstring>
 8 #include <climits>
 9 #include <iostream>
10 #include <algorithm>
11 #define INF 0x3f3f3f3f
12 #define LL long long
13 using namespace std;
14 const int MAX = 1e5 + 10;
15 
16 int a[MAX], b[MAX], c[MAX], vis[MAX], n, t, ans;
17 
18 int main()
19 {
20     scanf("%d", &t);
21     while (t --)
22     {
23         scanf("%d", &n);
24         for (int i = 1; i <= n; ++ i)
25         {
26             scanf("%d", &a[i]);
27             vis[i] = 0;
28         }
29         for (int i = 1; i <= n; ++ i)
30             scanf("%d", &b[i]);
31         for (int i = 1; i <= n; ++ i)
32             c[a[i]] = b[i];
33 
34         ans = n;
35         for (int i = 1; i <= n; ++ i)
36         {
37             int temp = i;
38             if (vis[temp]) continue;
39             if (temp != c[temp])
40             {
41                 ans --;
42                 while (!vis[temp])
43                 {
44                     vis[temp] = 1;
45                     temp = c[temp];
46                 }
47             }
48         }
49         printf("%d
", ans);
50     }
51     return 0;
52 }