제출 #446267

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
446267		zxcvbnm	Vudu (COCI15_vudu)	C++14	140 / 140	378 ms	39460 KiB

vudu

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
struct Ft {
    vector<ll> bit;
    int n;
    void build(vector<ll> a) {
        n = a.size()+2;
        bit.assign(n+2, 0);
    }
    void update(int idx, int x) {
        while(idx <= n) {
            bit[idx] += x;
            idx += idx & -idx;
        }
    }
    ll sum(int idx) {
        ll sum = 0;
        while(idx > 0) {
            sum += bit[idx];
            idx -= idx & -idx;
        }
        return sum;
    }
};
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
//    freopen("test.in", "r", stdin);
    int n;
    cin >> n;
    vector<int> a(n);
    for(int& i : a) {
        cin >> i;
    }

    int p;
    cin >> p;
    vector<ll> sum = {0};
    for(int i : a) {
        sum.push_back(sum.back()+(i-p));
    }

    vector<ll> sums = sum;
    sort(sums.begin(), sums.end());

    Ft ft;
    ft.build(sums);
    ll ans = 0;
    for(ll i : sum) {
        int idx = lower_bound(sums.begin(), sums.end(), i) - sums.begin();
        ans += ft.sum(idx+1);
        ft.update(idx+1, +1);
    }
    cout << ans << "\n";
    return 0;
}

• Subtask 1: 140 / 140