1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (b); i >= (a); i--)
#define SZ(x) ((int)x.size())
#define all(x) x.begin(), x.end()
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define st first
#define nd second
using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
auto &operator<<(auto &o, pair<auto, auto> p) {
    return o << "(" << p.st << ", " << p.nd << ")";
}
auto operator<<(auto &o, auto x)->decltype(end(x), o) {
    o << "{"; int i=0; for(auto e: x) o << ", " + 2*!i++ << e;
    return o << "}";
}
#define deb(x...) cerr << "[" #x "]: ", [](auto...$) { ((cerr<<$<<"; "),...) << endl; }(x)

const int MX = 69 * 1000 * 1000;
int cnt[MX];
const int OFFSET = MX / 2;

const int nax = 505;
int n;
int a[nax];

vector<int> trzeci;

void dodaj(int x){
    cnt[OFFSET + x] += 1;
}

void solve(){
    cin >> n;
    rep(i, 1, n) cin >> a[i];
    rep(i, 1, n){
        int sum = 0;
        rep(j, i, n){
            sum += a[j];
            trzeci.pb(sum);
        }
    }
   
    int prefix = 0;
    ll ans = 0;
    rep(k, 1, n){
        for(int x : trzeci){
            int adding = x - prefix;
            dodaj(adding);
        }
        prefix += a[k];

        for(int x : trzeci){
            int mam = x + prefix;
            int chce = -mam;
            ans += cnt[OFFSET + chce];
        }
    }
    
    for(int x : trzeci){
        if(x == 0) ans -= 1;
    }
    rep(i, 0, MX - 1) cnt[i] = 0;
    for(int x : trzeci) dodaj(x);
    for(int x : trzeci){
        cnt[OFFSET + x] -= 1;
        int mam = x + x;
        ans -= 3LL * cnt[OFFSET - mam];
        dodaj(x);
    }
    cout << ans / 6 << "\n";
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int tt = 1;
    // cin >> tt;
    rep(te, 1, tt) solve();
    return 0;
}