hdu 5363Key Set

題目連接：http://acm.hdu.edu.cn/showproblem.php?pid=5363

Problem Description

soda has a set  S with n integers {1,2,…,n}. A set is called key set if the sum of integers in the set is an even number. He wants to know how many nonempty subsets of S are key set.

 

 

Input

There are multiple test cases. The first line of input contains an integer  T (1≤T≤105), indicating the number of test cases. For each test case:

The first line contains an integer n (1≤n≤109), the number of integers in the set.

 

 

Output

For each test case, output the number of key sets modulo 1000000007.

 

 

Sample Input

4 1 2 3 4

 

 

Sample Output

0 1 3 7

 一看數據就是快速冪，一開始用int錯了，索性全改成long long

 1 #include <iostream>
 2 #include <cmath>
 3 using namespace std;
 4 
 5 long long f(long long a)
 6 {
 7     long long temp=2;
 8     long long ans=1;
 9     while (a)
10     {
11           if (a%2!=0)
12           ans*=temp;
13           
14           ans=ans%1000000007;
15           temp=temp*temp;
16           temp=temp%1000000007;
17           a/=2;
18     }
19     return ans;
20 }
21 int main()
22 {
23      long long n,m;
24      cin>>n;
25      while (n--)
26      {
27            cin>>m;
28            cout <<f(m-1)-1<<endl;
29      }
30      return 0;
31 }

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