Submission #1075392

#	Time	Username	Problem	Language	Result	Execution time	Memory
1075392		juicy	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	207 ms	76044 KiB

shoes

#include "shoes.h"

#include <bits/stdc++.h>

using namespace std;

long long count_swaps(vector<int> s) {
    int n = s.size();
    vector<int> ft(n + 1);
    auto up = [&](int i, int x) {
        for (; i; i -= i & -i) {
            ft[i] += x;
        }
    };
    auto qry = [&](int i) {
        int res = 0;
        for (; i <= n; i += i & -i) {
            res += ft[i];
        }
        return res;
    };
    map<int, deque<int>> dq;
    long long res = 0;
    for (int i = 0; i < n; ++i) {
        if (dq.count(-s[i]) && dq[-s[i]].size()) {
            int j = dq[-s[i]].front(); dq[-s[i]].pop_front();
            up(j + 1, 1);
            res += qry(j + 2) + (s[i] < 0);
        } else {
            dq[s[i]].push_back(i);
            up(i + 1, 1);
        }
    }
    return res;
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 15 / 15