Submission #332112

#	Time	Username	Problem	Language	Result	Execution time	Memory
332112		Sara	Mountains (NOI20_mountains)	C++14	100 / 100	474 ms	31200 KiB

Mountains

#include <bits/stdc++.h>
     
using namespace std;
     
#define ll long long int 
#define F first
#define S second
#define pb push_back
#define lc (ind * 2)
#define rc (lc + 1)
#define md ((b + e) / 2)

const ll N = 3e5 + 5;
const ll LOG = 20;
const int MOD = 1e9 + 7;
const ll INF = 1e18 + 10;

int n, cnt[4 * N];
ll H[N], ans;
vector <int> all[N];
vector <ll> vc;

void add(int id, int b = 0, int e = n, int ind = 1){
    if (b + 1 == e){
        cnt[ind] ++;
        return;   
    }
    if (id < md) add(id, b, md, lc);
    else add(id, md, e, rc);
    cnt[ind] = cnt[lc] + cnt[rc];
    return;
}
int get(int l, int r, int b = 0, int e = n, int ind = 1){
    if (l <= b && e <= r){
        return cnt[ind];
    }
    int res = 0;
    if (l < md) res += get(l, r, b, md, lc);
    if (md < r) res += get(l, r, md, e, rc);
    return res;
}
int main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    cin >> n;
    for (int i = 0; i < n; i++){
        cin >> H[i];
        vc.pb(H[i]);
    }
    sort(vc.begin(), vc.end());
    vc.resize(unique(vc.begin(), vc.end()) - vc.begin());
    for (int i = 0; i < n; i++){
        int p = lower_bound(vc.begin(), vc.end(), H[i]) - vc.begin();
        all[p].pb(i);
    }
    for (int i = 0; i < (int)vc.size(); i++){
        ll L, R;
        for (int j : all[i]){
            L = 0; R = 0;
            if (j) L = get(0, j);
            R = get(j, n);
            ans += (L * R);
        }
        for (int j : all[i]){
            add(j);
        }
    }
    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