题目链接

这个题关键是想明白，K的含义，即，向前跃进几步

代码如下

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define inf 1000000000
 4 #define maxn 200005
 5 vector<int> d[maxn];
 6 int p[maxn], c[maxn];
 7 bool vis[maxn];
 8 int cal(vector<int> loop)
 9 {
10     int minn = inf;
11     for(int k = 0; k < d[loop.size()].size(); k++){
12         int len = d[loop.size()][k];
13         for(int i = 0; i < len; i++){
14             bool flag = true;
15             for(int j = i; j < loop.size(); j += len){
16                 if(c[loop[i]] != c[loop[j]]){
17                     flag = false;
18                     break;
19                 }
20             }
21             if(flag) minn = min(minn, len);
22         }
23 
24     }
25     return minn;
26 }
27 int main()
28 {
29     for(int i = 1; i <= maxn; i++)
30         for(int j = i; j < maxn; j+= i)
31         d[j].push_back(i);
32     int t;
33     cin >> t;
34     while(t--){
35         int n;
36         cin >> n;
37         for(int i = 1; i <= n; i++) cin >> p[i];
38         for(int i = 1; i <= n; i++) cin >> c[i];
39         for(int i = 0; i <= n; i++) vis[i] = false;
40         int ans = n;
41         for(int i = 1; i <= n; i++){
42             if(vis[i]) continue;
43             int k = i;
44             vector<int> loop;
45             while(!vis[k]){
46                 loop.push_back(k);
47                 vis[k] = true;
48                 k = p[k];
49             }
50             ans = min(ans, cal(loop));
51         }
52         cout << ans << endl;
53 
54     }
55 }