POJ 2470

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<vector>
 4 using namespace std;
 5 
 6 int main()
 7 {
 8     //freopen("acm.acm","r",stdin);
 9     vector<int> coll;
10     int num;
11     int a;
12     int i;
13     bool * boo;
14     while(1)
15     {
16     scanf("%d",&num);
17     if(num == 0)
18         break;
19     boo = new bool[num];
20     memset(boo,false,sizeof(bool)*num);
21     for(i = 0; i < num; ++ i)
22     {
23         scanf("%d",&a);
24         coll.push_back(a);
25     }
26     for(i = 0; i < num; ++ i)
27     {
28         if(boo[i])
29         {
30             continue;            
31         }
32         else
33         {
34         if(coll[coll[i] - 1] != i +1)
35         {
36             cout<<"not ambiguous"<<endl;
37             break;
38         }
39         else
40         {
41             boo[coll[i] - 1] = true;
42             //boo[i] = true;
43         }
44 
45         }
46 
47     }
48     if(i == num)
49     {
50         cout<<"ambiguous"<<endl;
51     }
52     delete[] boo;
53     coll.clear();
54     }
55 }