Submission #259076

#	Time	Username	Problem	Language	Result	Execution time	Memory
259076		ryangohca	Mountains (NOI20_mountains)	C++17	100 / 100	1321 ms	27360 KiB

Mountains

#include <bits/stdc++.h>
#define pii pair<int, int>
#define db(x) cerr << #x << "=" << x << endl
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << endl
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<endl
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<pair<long long, int>, null_type, less<pair<long long, int>>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
main(){
	ordered_set left1, right1;
	int n; cin >> n;
	vector<long long> nums;
	for (int i = 0; i < n; i++){
		long long g; cin >> g;
		nums.push_back(g);
		right1.insert({g, i});
	}
	long long ans = 0;
	for (int i = 0; i < n; i++){
		right1.erase({nums[i], i});
		ans += left1.order_of_key({nums[i], 0LL}) * right1.order_of_key({nums[i], 0LL});
		left1.insert({nums[i], i});
	}
	cout << ans << endl;
}

Compilation message (stderr)

Mountains.cpp:11:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^

• 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