Sumsets
| Time Limit: 2000MS | Memory Limit: 200000K | |
| Total Submissions: 11892 | Accepted: 4782 |
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).
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).
Input
A single line with a single integer, N.
Output
The number of ways to represent N as the indicated sum. Due to the potential huge size of this number, print only last 9 digits (in base 10 representation).
Sample Input
7
Sample Output
6
Source
#include <cstdio>
int a[1000005];
int mod=1e9;
int dp[355][355];
int main ()
{int i,n;
a[1]=1;
a[2]=2;
for(i=3;i<=1000000;i++)
if(i&1) a[i]=a[i-1];
else a[i]=(a[i-2]+a[i>>1])%mod;
while(~scanf("%d",&i))
{
printf("%d\n",a[i]);
}
return 0;
}
好经典的题目。居然a[2]忘记给值了~
