Submission #1205985

#	Time	Username	Problem	Language	Result	Execution time	Memory
1205985		jer033	Arranging Shoes (IOI19_shoes)	C++20	45 / 100	146 ms	13944 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;

ll inversion_count(vector<int> s)
{
    int n = s.size();
    if (n<=1)
        return 0;
    vector<int> l;
    vector<int> r;
    for (int i=0; i<(n/2); i++)
        l.push_back(s[i]);
    for (int i=n/2; i<n; i++)
        r.push_back(s[i]);
    ll k = 0;
    ll m = 0;
    ll ans = inversion_count(l) + inversion_count(r);
    sort(l.begin(), l.end());
    sort(r.begin(), r.end());
    while ((k<(n/2)) and (m<((n+1)/2)))
    {
        if (l[k] > r[m])
        {
            ll add = (n/2) - k;
            ans += add;
            m++;
        }
        else
            k++;
    }
    return ans;
}

long long count_swaps(std::vector<int> s) {
	int n = (s.size())/2;
    vector<int> left_shoe_count(n+1, 0);
    vector<int> right_shoe_count(n+1, 0);
    map<pii, int> renumber;
    vector<int> new_s(2*n);
    int c = 1;
    for (int i=0; i<(2*n); i++)
        if (s[i] < 0)
        {
            left_shoe_count[0-s[i]]++;
            renumber[{0-s[i], left_shoe_count[0-s[i]]}] = c;
            new_s[i] = c;
            c+=2;
        }
    for (int i=0; i<(2*n); i++)
        if (s[i] > 0)
        {
            right_shoe_count[s[i]]++;
            new_s[i] = 1 + renumber[{s[i], right_shoe_count[s[i]]}];
        }
    return inversion_count(new_s);
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15