Submission #585886

#	Time	Username	Problem	Language	Result	Execution time	Memory
585886		Mystic03	Mountains (NOI20_mountains)	C++17	2 / 100	286 ms	17948 KiB

Mountains

#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>
#include <unordered_map>
using namespace std;

#define int long long

struct segmentTree {
    int n;
    vector<int> st;
    segmentTree(int n) {
        int x = (int)(ceil(log2(n)));
        int max_size = 2 * (int)pow(2, x) - 1;
        this->n = n;
        st.resize(max_size, 0);
    }
    void build(int startRange, int endRange, int currNode, vector<int> const& v) {
        if (startRange == endRange) {
            st[currNode] = v[startRange];
            return;
        }
        int mid = (startRange + endRange) / 2;
        build(startRange, mid, currNode * 2 + 1, v);
        build(mid + 1, endRange, currNode * 2 + 2, v);

        st[currNode] = st[currNode * 2 + 1] + st[currNode * 2 + 2];
    }
    void build(vector<int>const& v) {
        build(0, n - 1, 0, v);
    }

    int query(int startRange, int endRange, int l, int r, int currNode) {
        if (endRange < l || startRange > r) return 0;

        if (startRange >= l && endRange <= r) return st[currNode];

        int mid = (startRange + endRange) / 2;

        return (query(startRange, mid, l, r, currNode * 2 + 1) + query(mid + 1, endRange, l, r, currNode * 2 + 2));

    }

    int query(int l, int r) {
        return query(0, n - 1, l, r, 0);
    }


    void update(int startRange, int endRange, int currNode, int index, int val) {
        if (startRange == endRange) {
            st[currNode] = val;
            return;
        }
        int mid = (startRange + endRange) / 2;
        if (index <= mid) {
            update(startRange, mid, currNode * 2 + 1, index, val);
        }
        else {
            update(mid + 1, endRange, currNode * 2 + 2, index, val);
        }

        st[currNode] = st[currNode * 2 + 1] + st[currNode * 2 + 2];
    }
    void update(int index, int val) {
        update(0, n - 1, 0, index, val);
    }
};

int32_t main() {
	int n;
	cin >> n;
	vector<pair<int,int>> v(n);
	
    vector<int> elements(n,0);
	for (int i = 0; i < n; i++) {
		int x;
		cin >> x;
		v[i] = { x,i };
	}
	sort(v.begin(), v.end());

    segmentTree tr(n);
    tr.build(elements);
	vector<int> index;
	int cnt = 0;
    index.push_back(v[0].second);

	for (int i = 1; i < n; i++) {
		index.push_back(v[i].second);
		if(v[i].first != v[i - 1].first) {
			for(int x : index){
				tr.update(x, 1);
			}
			index.clear();
		}
		cnt += tr.query(0, v[i].second - 1) * tr.query(v[i].second + 1, n - 1);
	}

    cout << cnt << endl;


}

• Subtask 1: 2 / 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