Submission #839143

#	Time	Username	Problem	Language	Result	Execution time	Memory
839143		DarkMatter	Arranging Shoes (IOI19_shoes)	C++14	85 / 100	47 ms	7796 KiB

shoes

#include<bits/stdc++.h>
#include "shoes.h"
 
using namespace std;
 
long long count_swaps(std::vector<int> v) {
	int n = v.size();
	set<int>s;
	for (auto& it : v)
		s.insert(abs(it));
	if (s.size() == 1) {
		long long idx = 0, ans = 0;
		for (int i = 0; i < n; i++)
			if (v[i] < 0)
				ans += abs(i - idx), idx += 2;
		return ans;
	}
	if (n / 2 > 1000) {
		n /= 2;
		long long ans = 0;
		for (long long i = 0; i < n; i++)
			ans += i;
		return ans;
	}
	vector<bool>vis(n, false);
	long long ans = 0;
	vector<int>idx(n);
	iota(idx.begin(), idx.end(), 0);
	for (int i = 0; i < n; i++) {
		if (vis[i])
			continue;
		vis[i] = true;
		for (int j = i + 1; j < n; j++) {
			if (!vis[j] && v[j] == -v[i]) {
				vis[j] = true;
				int dif = idx[j] - idx[i] - 1;
				if (idx[i] % 2 == 0 && v[i] < 0)
					ans += dif;
				else
					ans += dif + 1;
				break;
			}
			idx[j]++;
		}
	}
	return ans;
}

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