Submission #1281983

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281983		cheska	Mountains (NOI20_mountains)	C++20	24 / 100	395 ms	26576 KiB

Mountains

#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define ppii pair<pii, pii> 
#define tiii tuple<int, int, int>
#define g0 get<0>
#define g1 get<1>
#define g2 get<2>
#define f first
#define s second
#define pb push_back
const int N = 5005;
const int MOD = 1e9+7;
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> 
vector<int> compress(vector<int> b, int n) {
    map<int, int> m;
    vector<pii> c(n);
    for (int i = 0; i < n; i++) {
        c[i] = {b[i], i};
    }
    sort(c.begin(), c.end());
    int cr = 0;
    for (int i = 0; i < n; i++) {
        if (m.count(c[i].f)) b[c[i].s] = m[c[i].f];
        else {
            b[c[i].s] = cr;
            m[c[i].f] = cr;
            cr++;
        }
    }
    return b;
}
signed main() {
   // freopen("in.in", "r", stdin);
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n; cin >> n;
    vector<int> b(n);
    map<int, vector<int>> a;
    for (int i = 0; i < n; i++) {
        cin >> b[i];
    }
    b = compress(b, n);
    for (int i = 0; i < n; i++) {
        a[b[i]].pb(i);
    }
    ordered_set ss;
    long long ans = 0;
    for (auto i : a) {
        for (int j : i.s) {
            int k = ss.order_of_key(j);
            ans += k*(ss.size()-k);
        }
        for (int j : i.s) {
            ss.insert(j);
        }
    }
    cout << ans;
}

• Subtask 1: 2 / 2
• Subtask 2: 4 / 4
• Subtask 3: 9 / 9
• Subtask 4: 0 / 36
• Subtask 5: 0 / 28
• Subtask 6: 9 / 9
• Subtask 7: 0 / 12