# BZOJ 1677: [Usaco2005 Jan]Sumsets 求和

## 1677: [Usaco2005 Jan]Sumsets 求和

Time Limit: 5 Sec  Memory Limit: 64 MB
Submit: 617  Solved: 344
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## Description

Farmer John commanded his cows to search for different sets of numbers that sum to a given number. The cows use only numbers that are an integer power of 2. Here are the possible sets of numbers that sum to 7: 1) 1+1+1+1+1+1+1 2) 1+1+1+1+1+2 3) 1+1+1+2+2 4) 1+1+1+4 5) 1+2+2+2 6) 1+2+4 Help FJ count all possible representations for a given integer N (1 <= N <= 1,000,000).

一个整数N.

7

## Sample Output

6

1) 1+1+1+1+1+1+1
2) 1+1+1+1+1+2
3) 1+1+1+2+2
4) 1+1+1+4
5) 1+2+2+2
6) 1+2+4

### 代码

 1 /*Author:WNJXYK*/
2 #include<cstdio>
3 using namespace std;
4
5 const int N=1000005;
6 int f[N], n;
7
8 int main() {
9     scanf("%d",&n);
10     f[1]=1;
11     for(int i=2;i<=n;i++) {
12         f[i]=f[i-1];
13         if(!(i&1)) f[i]+=f[i>>1];
14         f[i]%=1000000000;
15     }
16     printf("%d\n",f[n]);
17     return 0;
18 }
View Code

posted @ 2014-11-04 10:02  WNJXYK  阅读(111)  评论(0编辑  收藏  举报