Submission #915647

#	Time	Username	Problem	Language	Result	Execution time	Memory
915647		SmuggingSpun	Arranging Shoes (IOI19_shoes)	C++14	10 / 100	1 ms	756 KiB

shoes

#include "shoes.h"
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll count_swaps(vector<int>s) {
	int n = s.size();
	map<int, int>p;
	vector<int>a(n);
	for(int i = 0, index = 1; i < n; i++){
		auto it = p.find(-s[i]);
		if(it != p.end()){
			a[i] = it->second + (s[i] < 0 ? -1 : 1);
			p.erase(it);
		}
		else{
			p[s[i]] = a[i] = index + int(s[i] > 0);
			index += 2;
		}
	}
	vector<int>bit(n + 1, 0);
	auto update = [&] (int p){
		for(; p <= n; p += p & -p){
			bit[p]++;
		}
	};
	auto get = [&] (int p){
		int ans = 0;
		for(; p > 0; p -= p & -p){
			ans += bit[p];
		}	
		return ans;
	};
	ll ans = 0;
	for(int i = 0; i < n; i++){
		ans += i - get(a[i]);
		update(a[i]);
	}
	return ans;
}

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