[AHOI2009][BZOJ1800] fly 飞行棋|枚举|暴力

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
int n,ans,s[25];
inline int read()
{
    int a=0,f=1; char c=getchar();
    while (c<‘0‘||c>‘9‘) {if (c==‘-‘) f=-1; c=getchar();}
    while (c>=‘0‘&&c<=‘9‘) {a=a*10+c-‘0‘; c=getchar();}
    return a*f;
}
int main()
{
    n=read();
    for (int i=1;i<=n;i++)
    {
        int x=read();
        s[i]=s[i-1]+x;
    }
    for (int i=1;i<=n;i++)
        for (int j=i+1;j<=n;j++)
            for (int k=j+1;k<=n;k++)
                for (int l=k+1;l<=n;l++)
                    if (s[j]-s[i]==s[l]-s[k]&&s[n]-s[l]+s[i]==s[k]-s[j]) ans++;
    printf("%d",ans);
    return 0;
}