Submission #337336

#	Time	Username	Problem	Language	Result	Execution time	Memory
337336		iulia13	Mountains (NOI20_mountains)	C++14	100 / 100	895 ms	36588 KiB

Mountains

#include <bits/stdc++.h>

using namespace std;
#define ll long long
ll h[300005];
ll hh[300005];
map <ll, int> mp;
int v[300005];
int seg[12000005];
void update(int nod, int l, int r, int poz, int val)
{
    int mid;
    if (r == l)
    {
        seg[nod] += val;
        return;
    }
    mid = (l + r) / 2;
    if (poz <= mid)
        update (2 * nod, l, mid, poz, val);
    else
        update (2 * nod + 1, mid + 1, r, poz, val);
    seg[nod] = seg[2 * nod] + seg[2 * nod + 1];
}
int query (int nod, int l, int r, int ql, int qr)
{
    int mid;
    if (ql <= l&& r <= qr)
        return seg[nod];
    mid = (l + r) / 2;
    int s = 0;
    if (mid >= ql)
        s += query(2 * nod, l, mid, ql, qr);
    if (mid < qr)
        s += query(2 * nod + 1, mid + 1, r, ql, qr);
    return s;

}
int d[300005];
int main()
{
    int n, i;
    ll ans = 0;
    cin >> n;
    for (i = 1; i <= n; i++)
    {
        cin >> h[i];
        hh[i] = h[i];
    }
    sort (hh + 1, hh + n + 1);
    mp[hh[1]] = 1;
    int l = 1;
    for (i = 2; i <= n; i++)
    {
        if (hh[i] != hh[i - 1])
        {
            l++;
            mp[hh[i]] = l;
        }
    }
    for (i = 1; i <= n; i++)
        v[i] = mp[h[i]];
    for (i = 1; i <= n; i++)
    {
        if (v[i] - 1)
        d[i] = query(1, 1, n, 1, v[i] - 1);
        update(1, 1, n, v[i], 1);
    }
    for (i = 1; i <= 4 * n; i++)
        seg[i] = 0;
    for (i = n; i; i--)
    {
        if (v[i] - 1)
        ans += 1LL * query(1, 1, n, 1, v[i] - 1) * d[i];
        update(1, 1, n, v[i], 1);
    }
    cout << ans;
    return 0;
}

• Subtask 1: 2 / 2
• Subtask 2: 4 / 4
• Subtask 3: 9 / 9
• Subtask 4: 36 / 36
• Subtask 5: 28 / 28
• Subtask 6: 9 / 9
• Subtask 7: 12 / 12