Submission #1280439

#	Time	Username	Problem	Language	Result	Execution time	Memory
1280439		jackofall718	Mountains (NOI20_mountains)	C++20	0 / 100	1874 ms	327680 KiB

Mountains

#include <bits/stdc++.h>
#include <chrono>
#define ll long long int
#define endl '\n'
#define vn vector<ll>
#define vi vector<pair <ll,ll>>

using namespace std;
using namespace std::chrono;
const int MAX_N = 1e9 + 7;
#define pii pair<ll,ll>
const ll INF = 0x3f3f3f3f3f3f3f3f;

#define pb push_back  
#define srt(vp) sort(vp.begin(), vp.end()) 

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    auto start = high_resolution_clock::now();


    ll n;
    cin>>n;
    vn v(n+1);
    for (int i=1;i<=n;i++)cin>>v[i];
    ll ans = 0;
    map <ll,ll> count;
    for (int i=1;i<=n;i++)count[v[i]]++;
    map <ll,ll> cnt;
    for (int i=1;i<=n;i++){
        ll num1=0;
        ll num2=0;
        for (int j=0;j<v[i];j++){
            num1 += cnt[j];
            num2 += count[j]-cnt[j];
        }
        cnt[v[i]]++;
        ans += num1*num2;

    }
    cout<<ans<<endl;

    


    

    auto stop = high_resolution_clock::now();
    auto duration = duration_cast<microseconds>(stop - start);
    //cout << "Time taken by function: " << duration.count() << " microseconds" << endl;

    return 0;
}

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