neps468.cpp

/*
 * Contest : OBI 2019 - Fase 1
 * Problem : Soma
 * Link    : https://neps.academy/br/exercise/468
 */

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define fastio ios::sync_with_stdio(0); cin.tie(0);

int main() {
  fastio

  ll n, k, cnt = 0;
  cin >> n >> k;

  vector<ll> v(n), pref(n + 1);
  map<ll, ll> pref_cnt;

  for (int i = 0; i < n; i++) {
    cin >> v[i];
    pref[i + 1] = pref[i] + v[i];
  }

  for (int i = 1; i <= n; i++) fprintf(stderr, "%i ", pref[i]);
  fprintf(stderr, "\n");

  for (int i = 0; i <= n; i++) { // O(n) 
    cnt += pref_cnt[pref[i] - k];
    pref_cnt[pref[i]] += 1;
  }

  for (auto p : pref_cnt) fprintf(stderr, "%lli %lli\n", p.first, p.second);
  fprintf(stderr, "\n");

  printf("%i\n", cnt);

  return 0;
}