Submission #591664

#	Time	Username	Problem	Language	Result	Execution time	Memory
591664		lumibons	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	69 ms	14848 KiB

shoes

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

#define sz(x) ((int) (x).size())
typedef long long ll;

using namespace std;

int n, f[200100];
vector<int> p[200100];

void change(int i, int d) {
	for (i++; i <= 2 * n; i += i & -i)
		f[i] += d;
}

int sum(int i) {
	int s = 0;
	for (i++; i; i -= i & -i)
		s += f[i];
	return s;
}

ll count_swaps(vector<int> s) {
	n = sz(s) / 2;
	for (int i = 2 * n - 1; i >= 0; i--) {
		change(i, 1);
		s[i] = s[i] > 0 ? s[i] - 1 : -s[i] - 1 + n;
		p[s[i]].push_back(i);
	}
	ll r = 0;
	for (int i = 0; i < 2 * n; i++)
		if (s[i] >= 0) {
			int j = p[s[i] < n ? s[i] + n : s[i] - n].back();
			change(i, -1);
			change(j, -1);
			r += (s[i] < n) + sum(j);
			p[s[i]].pop_back();
			p[s[j]].pop_back();
			s[j] = -1;
		}
	return r;
}

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