POJ 2769

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<set>
 4 #define MAXN 305
 5 using namespace std;
 6 int a[MAXN];
 7 int mod[MAXN];
 8 set<int> coll;
 9 set<int>::iterator pos;
10 int main()
11 {
12     ///freopen("acm.acm","r",stdin);
13     int test;
14     int g;
15     int i;
16     bool boo;
17     int j;
18     int k;
19     int modo;
20     scanf("%d",&test);
21     while(test --)
22     {
23         scanf("%d",&g);
24         for(i = 0; i < g; ++ i)
25         {
26             scanf("%d",&a[i]);
27         }
28         for(j = g ;; ++ j)
29         {
30             boo = false;
31             for(i = 0; i < g; ++ i)
32             {
33                 mod[i] = a[i]%j;
34             }
35             for(i = 0; i < g; ++ i)
36             {
37                 for(k = i + 1; k < g; ++ k)
38                 {
39                     if(mod[i] == mod[k])
40                         //boo = true;
41                         break;
42                 }
43                 if(k < g)
44                     break;
45             }
46             if(i == g)
47             {
48                 printf("%d\n",j);
49                 break;
50             }
51         }
52     }
53 }