Submission #583325

#	Time	Username	Problem	Language	Result	Execution time	Memory
583325		Lucpp	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	140 ms	140168 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define sz(x) ((int)(x).size())

vector<int> fen;
void add(int i, int x){
	for(i++; i < sz(fen); i+=i&-i) fen[i] += x;
}
int qry(int i){
	int ans = 0;
	for(i++; i > 0; i-=i&-i) ans += fen[i];
	return ans;
}

ll count_swaps(vector<int> s) {
	ll ans = 0;
	fen.resize(sz(s)+1);
	vector<queue<int>> vl(sz(s)/2+1), vr(sz(s)/2+1);
	vector<pair<int, int>> v;
	for(int i = 0; i < sz(s); i++){
		if(s[i] > 0){
			if(vl[s[i]].empty()) vr[s[i]].push(i);
			else{
				v.emplace_back(vl[s[i]].front(), i);
				vl[s[i]].pop();
			}
		}
		else{
			if(vr[-s[i]].empty()) vl[-s[i]].push(i);
			else{
				ans++;
				v.emplace_back(vr[-s[i]].front(), i);
				vr[-s[i]].pop();
			}
		}
	}
	sort(v.begin(), v.end());
	for(auto [i, j] : v){
		int L = i+qry(i);
		int R = j+qry(j);
		ans += R-L-1;
		add(i, 1);
		add(j, -1);
	}
	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