题目传送门
1 /*
2 DFS：从大到小取模，因为对比自己大的数取模没意义，可以剪枝。但是我从小到大也过了，可能没啥大数据
3 */
4 /************************************************
5 Author :Running_Time
6 Created Time :2015-8-1 18:57:52
7 File Name :A.cpp
8 *************************************************/
9
10 #include <cstdio>
11 #include <algorithm>
12 #include <iostream>
13 #include <sstream>
14 #include <cstring>
15 #include <cmath>
16 #include <string>
17 #include <vector>
18 #include <queue>
19 #include <deque>
20 #include <stack>
21 #include <list>
22 #include <map>
23 #include <set>
24 #include <bitset>
25 #include <cstdlib>
26 #include <ctime>
27 using namespace std;
28
29 typedef long long ll;
30 const int MAXN = 22;
31 const int INF = 0x3f3f3f3f;
32 const int MOD = 1e9 + 7;
33 int a[MAXN];
34 bool vis[MAXN];
35 int n, ans;
36
37 bool cmp(int x, int y) {
38 return x > y;
39 }
40
41 void DFS(int now, int step) {
42 for (int i=1; i<=n; ++i) {
43 if (vis[i] || now < a[i]) continue;
44 if (now % a[i] == 0) {
45 ans = min (ans, step + 1); return ;
46 }
47 vis[i] = true; DFS (now % a[i], step + 1); vis[i] = false;
48 }
49 }
50
51 int main(void) { //HDOJ 5339 Untitled
52 int T; scanf ("%d", &T);
53 while (T--) {
54 int x; scanf ("%d%d", &n, &x);
55 for (int i=1; i<=n; ++i) scanf ("%d", &a[i]);
56 sort (a+1, a+1+n, cmp);
57 if (x < a[n]) {
58 puts ("-1"); continue;
59 }
60 memset (vis, false, sizeof (vis));
61 ans = INF; DFS (x, 0);
62 if (ans == INF) puts ("-1");
63 else printf ("%d
", ans);
64 }
65
66 return 0;
67 }