제출 #250400

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
250400		apostoldaniel854	Vudu (COCI15_vudu)	C++14	140 / 140	295 ms	28096 KiB

vudu

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
#define pb push_back
#define dbg(x) cerr << #x << " " << x << "\n"

const int N = 1e6;

int n, p;
int aib[1 + N + 2];
int a[1 + N];
int val[1 + N];


inline int lsb (int x) {
    return x & -x;
}

int qry (int pos) {
    int ans = 0;
    while (pos) {
        ans += aib[pos];
        pos -= lsb (pos);
    }
    return ans;
}

void upd (int pos, int val) {
    while (pos <= n + 2) {
        aib[pos] += val;
        pos += lsb (pos);
    }
}

int main () {
    ios::sync_with_stdio (false);
    cin.tie (0); cout.tie (0);

    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    cin >> p;
    vector <pair <ll, int>> v;
    v.pb ({0, 0});
    ll sum = 0;
    for (int i = 1; i <= n; i++) {
        a[i] -= p;
        sum += a[i];
        v.pb ({sum, i});
    }
    sort (v.begin (), v.end ());
    int cnt = 1;
    val[v[0].second] = cnt;
    for (int i = 1; i <= n; i++) {
        if (v[i].first != v[i - 1].first)
            cnt++;
        val[v[i].second] = cnt;
    }
    ll ans = 0;
    for (int i = 0; i <= n; i++) {
        ans += qry (val[i]);
        upd (val[i], 1);
    }
    cout << ans << "\n";
    return 0;
}

• Subtask 1: 140 / 140