Submission #826818

#	Time	Username	Problem	Language	Result	Execution time	Memory
826818		vjudge1	Arranging Shoes (IOI19_shoes)	C++17	65 / 100	22 ms	3692 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define en '\n'
#define all(v) v.begin(),v.end()
const int N = 3e5 + 10;
int a[N],b[N],n;
ll calc(vector <int> g) {
	for(int i = 1;i <= 2 * n;i++)b[i] = a[i];
	ll ans = 0;
	int last = 0;
	for(auto to : g) {
		for(int i = last + 1;i <= 2 * n;i++) {
			if(b[i] == -to) {
				for(int j = i - 1;j >= last + 1;j--) {
					ans++;
					swap(b[j],b[j + 1]);
				}
				break;
			}
		}
		last++;
		for(int i = last + 1;i <= 2 * n;i++) {
			if(b[i] == to) {
				for(int j = i - 1;j >= last + 1;j--) {
					ans++;
					swap(b[j],b[j + 1]);
				}
				break;
			}
		}
		last++;
	}
	return ans;
}
ll count_swaps(vector<int> S) {
	n = S.size();
	vector <int> q;
	for(int i = 0;i < n;i++) {
		a[i + 1] = S[i];
		if(S[i] > 0)q.pb(S[i]);
	}
	n /= 2;
	if(n > 8) {
		ll ans = 0;
		int L = 1;
		for(int i = 1;i <= 2 * n;i++) {
			if(a[i] < 0) {
				ans += abs(i - L);
				L += 2;
			}
		}
		return ans; 
	}
	sort(all(q));
	ll ans = calc(q);
	while(next_permutation(all(q))) {
		ans = min(ans,calc(q));
	}
	return ans;
}

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