제출 #585884

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
585884		teki	Mountains (NOI20_mountains)	C++11	100 / 100	125 ms	15272 KiB

Mountains

#include <bits/stdc++.h>

typedef long long ll;

#define pb push_back
#define MS(x,y) memset((x),(y),sizeof((x)))
const ll MN = 1000000007;

using namespace std;

ll n;
ll tree[300001];
ll niza[300001];

ll query(ll pos) {
    ll ret = 0;
    while (pos > 0) {
        ret += tree[pos];
        pos -= pos&(-pos);
    }
    return ret;
}

void update(ll pos, ll val) {
    while (pos <= n) {
        tree[pos] += val;
        pos += pos&(-pos);
    }
}

ll presmetaj (ll pos) {
    ll levo = query(pos-1);
    ll site = query(n);

    return levo*(site-levo);
}

int main()
{
    #if LOCAL_DEBUG
        fstream cin("in.txt");
    #endif

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    MS(tree,0);

    cin>>n;

    for (ll i = 1; i<=n; i++) cin>>niza[i];

    vector<pair<ll,ll>> sorti(n+1);
    for (ll i = 1; i<=n; i++) sorti[i] = {niza[i],i};
    sort(sorti.begin(),sorti.end());

    vector<ll> moment;
    ll sea = -1, res = 0;

    for (ll i = 1; i<=n; i++) {
        ll a = sorti[i].first;

        if (a != sea) {
            for (auto it:moment) res += presmetaj(it);
            for (auto it:moment) update(it,1);

            vector<ll> nov;
            swap(moment,nov);
        }

        sea = a;
        moment.pb(sorti[i].second);
    }

    for (auto it:moment) res += presmetaj(it);

    cout<<res<<endl;

    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