Submission #295047

#	Time	Username	Problem	Language	Result	Execution time	Memory
295047		SamAnd	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	457 ms	275064 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
typedef long long ll;
const int N = 200005;

int n;
int a[N];

int t[N * 4];
void ubd(int tl, int tr, int x, int y, int pos)
{
    if (tl == tr)
    {
        t[pos] = y;
        return;
    }
    int m = (tl + tr) / 2;
    if (x <= m)
        ubd(tl, m, x, y, pos * 2);
    else
        ubd(m + 1, tr, x, y, pos * 2 + 1);
    t[pos] = t[pos * 2] + t[pos * 2 + 1];
}

int qry(int tl, int tr, int l, int r, int pos)
{
    if (l > r)
        return 0;
    if (tl == l && tr == r)
    {
        return t[pos];
    }
    int m = (tl + tr) / 2;
    return (qry(tl, m, l, min(m, r), pos * 2) +
            qry(m + 1, tr, max(m + 1, l), r, pos * 2 + 1));
}

deque<int> l[N], r[N];

long long count_swaps(std::vector<int> s)
{
    n = sz(s) / 2;
    for (int i = 1; i <= n * 2; ++i)
        a[i] = s[i - 1];

    for (int i = 1; i <= n * 2; ++i)
    {
        ubd(1, n * 2, i, 1, 1);
        if (a[i] < 0)
            l[-a[i]].push_back(i);
        else
            r[a[i]].push_back(i);
    }

	ll ans = 0;
	for (int i = 1; i <= n * 2; ++i)
    {
        if (qry(1, n * 2, i, i, 1) == 0)
            continue;
        ans += qry(1, n * 2, min(l[abs(a[i])].front(), r[abs(a[i])].front()),
                                max(l[abs(a[i])].front(), r[abs(a[i])].front()), 1) - 2;
        if (a[i] > 0)
            ++ans;
        ubd(1, n * 2, l[abs(a[i])].front(), 0, 1);
        ubd(1, n * 2, r[abs(a[i])].front(), 0, 1);
        l[abs(a[i])].pop_front();
        r[abs(a[i])].pop_front();
    }
    return ans;
}

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