1800: [Ahoi2009]fly 飞行棋

 1 #include<iostream>
 2 #include<cstdio>
 3 using namespace std;
 4 
 5 int n,ans;
 6 int a[30];
 7 
 8 int main()
 9 {
10     scanf("%d",&n);
11     for(int i=1;i<=n;i++)
12     {
13         scanf("%d",&a[i]);
14         a[i]+=a[i-1];
15     }
16     for(int i=1;i<=n;i++)
17         for(int j=i+1;j<=n;j++)
18             for(int k=j+1;k<=n;k++)
19                 for(int l=k+1;l<=n;l++)
20                     if((a[j]-a[i]==a[l]-a[k])&&(a[n]-(a[l]-a[i])==a[k]-a[j]))
21                         ans++;
22     printf("%d",ans);
23     return 0;
24 }