Submission #259697

#	Time	Username	Problem	Language	Result	Execution time	Memory
259697		IOrtroiii	Mountains (NOI20_mountains)	C++14	100 / 100	817 ms	29688 KiB

Mountains

#include <bits/stdc++.h>

#include <ext/pb_ds/tree_policy.hpp>

#include <ext/pb_ds/assoc_container.hpp>

using namespace std;

using namespace __gnu_pbds;

template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

int main() {
   ios_base::sync_with_stdio(false); cin.tie(nullptr);
   int N; cin >> N;
   vector<int64_t> H(N);
   for (int i = 0; i < N; ++i) cin >> H[i];
   vector<int> L(N), R(N);
   ordered_set<pair<int64_t, int>> st;
   for (int i = 0; i < N; ++i) {
      L[i] = st.order_of_key({H[i], -1});
      st.insert({H[i], i});
   }
   st.clear();
   for (int i = N - 1; i >= 0; --i) {
      R[i] = st.order_of_key({H[i], -1});
      st.insert({H[i], i});
   }
   int64_t ans = 0;
   for (int i = 0; i < N; ++i) ans += int64_t(L[i]) * R[i];
   cout << ans << '\n';
   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