Submission #1227554

#	Time	Username	Problem	Language	Result	Execution time	Memory
1227554		overwatch9	Mountains (NOI20_mountains)	C++20	100 / 100	630 ms	37988 KiB

Mountains

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
struct stree {
    #define lc v*2
    #define rc v*2+1
    vector <int> tree;
    stree (int s) {
        tree.resize(s*4);
    }
    void pushup(int v) {
        tree[v] = tree[lc] + tree[rc];
    }
    void update(int v, int tl, int tr, int p) {
        if (tl > p || tr < p)
            return;
        if (tl == tr) {
            tree[v] = 1;
            return;
        }
        int tm = (tl + tr) / 2;
        update(lc, tl, tm, p);
        update(rc, tm+1, tr, p);
        pushup(v);
    }
    int query(int v, int tl, int tr, int l, int r) {
        if (tl > r || tr < l)
            return 0;
        if (tl >= l && tr <= r)
            return tree[v];
        int tm = (tl + tr) / 2;
        int a = query(lc, tl, tm, l, r);
        int b = query(rc, tm+1, tr, l, r);
        return a + b;
    }
};
int main() {
    int n;
    cin >> n;
    map <ll, vector <int>> mp;
    for (int i = 0; i < n; i++) {
        ll x;
        cin >> x;
        mp[x].push_back(i);
    }
    stree tree(n);
    ll ans = 0;
    for (auto it : mp) {
        for (auto i : it.second) {
            ll l = tree.query(1, 0, n, 0, i);
            ll r = tree.query(1, 0, n, i, n);
            ans += l * r;
        }
        for (auto i : it.second) {
            tree.update(1, 0, n, i);
        }
    }
    cout << ans << '\n';
}

• 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