usaco subset

#include<stdio.h>int n;long long f[40][2000];int main(){freopen("subset.in","r",stdin);freopen("subset.out","w",stdout);int i,j;scanf("%d",&n);f[1][1]=1;for (i=2;i<=n;i++)for (j=1;j<=i*(i+1)/2;j++) {f[i][j]=f[i-1][j];if (j>=i) f[i][j]+=f[i-1][j-i];}if (n*(n+1)/2%2==1) printf("0\n"); else printf("%lld\n",f[n][n*(n+1)/2/2]);return 0;}