UVa 10609 (计数 公式推导) Teams

 1 #include <cstdio>
 2 
 3 typedef long long LL;
 4 const LL M = 1000000007;
 5 
 6 LL pow(int p)
 7 {
 8     LL ans = 1, base = 2;
 9     while(p)
10     {
11         if(p & 1) ans = (ans * base) % M;
12         p >>= 1;
13         base = (base * base) % M;
14     }
15     return ans;
16 }
17 
18 int main()
19 {
20     //freopen("in.txt", "r", stdin);
21     int T;
22     scanf("%d", &T);
23     for(int kase = 1; kase <= T; kase++)
24     {
25         int n;
26         scanf("%d", &n);
27         LL ans = pow(n-1);
28         printf("Case #%d: %lld\n", kase, (ans * n) % M);
29     }
30 
31     return 0;
32 }