题目链接https://ac.nowcoder.com/acm/contest/297/B
#include<stdio.h>
double a[100009];
int main()
{
double sum=0,n;
scanf("%lf",&n);
for(int i=1;i<=n;i++)
{
scanf("%lf",&a[i]);
sum+=a[i];
}
int u=0;
for(int i=1;i<=n;i++)
{
if(a[i]*2 == sum)
{
u++;
}
}
if(u == 0)
{
printf("-1\n");
}
else{printf("%d\n",u);
}
return 0;
}