Submission #887873

#	Time	Username	Problem	Language	Result	Execution time	Memory
887873		vjudge1	Mountains (NOI20_mountains)	C++17	100 / 100	495 ms	45280 KiB

Mountains

#include <iostream>
using namespace std;
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
#define int long long
namespace __gnu_pbds{
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
}
using namespace __gnu_pbds;
int a[300005], f[300005], g[300005];
signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int n, res = 0;
    cin >> n;
    ordered_set s, t;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        f[i] = s.order_of_key(a[i]);
        s.insert(a[i]);
    }
    for (int i = n; i >= 1; i--) {
        g[i] = t.order_of_key(a[i]);
        t.insert(a[i]);
        res += f[i] * g[i];
    }
    cout << res;
}

• 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