Submission #723927

#	Time	Username	Problem	Language	Result	Execution time	Memory
723927		adrilen	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	117 ms	22216 KiB

shoes

#include "shoes.h"
#include<bits/stdc++.h>

using namespace std;
using ll = long long;

constexpr int maxn = 2e5, bits = 18, siz = 1 << bits;

int segtree[siz * 2] = { 0 };

void update(int p)
{
    while (p > 0)
    {
        segtree[p]++;
        p /= 2;
    }
}

ll query(int pos, int l, int r, int gl, int gr)
{
    if (l > gr || gl > r) return 0;
    if (gl <= l && r <= gr) return segtree[pos];

    int mid = (l + r) >> 1;
    return query(pos * 2, l, mid, gl, gr) + query(pos * 2 + 1, mid + 1, r, gl, gr);
}


int n;

// Shoe types
set <int> shoes[maxn / 2 + 5][2];

ll count_swaps(vector<int> s) {
    n = s.size();

    ll output = 0;

    for (int i = 0; i < n; i++)
    {
        if (s[i] > 0) shoes[s[i]][1].insert(i); // Right
        else shoes[abs(s[i])][0].insert(i);          // Left
    }

    ll typ, next_pair;
    for (ll i = 0; i < n; i++)
    {
        if (segtree[i + siz]) continue;

        typ = (s[i] > 0);
        shoes[abs(s[i])][typ].erase(i);
        next_pair = *shoes[abs(s[i])][(typ + 1) & 1].begin();
        shoes[abs(s[i])][(typ + 1) & 1].erase(next_pair);


        // cout << i << " " << next_pair << " " << output << " ";
        // cout << query(1, 0, siz - 1, i, next_pair) << "\n";
        output += next_pair - i - query(1, 0, siz - 1, i, next_pair) + typ - 1;

        // update(i + siz);
        update(next_pair + siz);
    }

    return output;
}

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