为什么我这个代码在谷能AC，在一本通最后一个点现实答案错误，求解

#include <iostream>
#include <algorithm>
#include <iomanip>
using namespace std;
int n;
double sum, curr;
struct item{
    int id;//序号
    int time;//打水时间
}arr[1111];
bool cmp(item x, item y) {
    if(x.time == y.time) {
        return x.id < y.id;
    }
    return x.time < y.time;
}
int main(){
    cin >> n;
    for(int i = 1; i <= n; i++) {
        int x;
        cin >> x;
        arr[i].id = i;
        arr[i].time = x;
    }
    sort(arr + 1, arr + n + 1, cmp);
    for(int i = 1; i < n; i++) {
        curr += arr[i].time;
        sum += curr;
    }
    for(int i = 1; i <= n; i++) {
        cout << arr[i].id << " ";
    }
    cout << endl;
    cout << fixed << setprecision(2) << sum / n << endl;
    return 0;
}