Submission #433207

#	Time	Username	Problem	Language	Result	Execution time	Memory
433207		kostia244	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	479 ms	27076 KiB

shoes

#include "shoes.h"
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) begin(x), end(x)
long long count_swaps(std::vector<int> s) {
	ll res = 0;
	int n = s.size()/2;
	vector<ll> fen(2*n+1);
	auto add = [&](int x) {
		for(; x <= 2*n; x += x&-x) fen[x]++;
	};
	auto get = [&](int x) {
		int res = 0;
		add(x);
		for(; x; x -= x&-x)
			res += fen[x];
		return res;
	};
	vector<int> b(2*n);
	map<int, vector<int>> ass;
	for(int i = 0; i < 2*n; i++) ass[s[i]].push_back(i);
	for(auto &[a, b] : ass) reverse(all(b));

	vector<int> v(2*n, -69);
	for(int j = 0, i = 0; i < 2*n; i++) if(-69 == v[i]) {
		v[i] = ++j;
		v[ass[-s[i]].back()] = ++j;
		ass[s[i]].pop_back();
		ass[-s[i]].pop_back();
		res += s[i] > 0;
	}
	//for(auto &i : v) cout << i << " "; cout << endl;
	for(int i = 0; i < 2*n; i++) b[v[i]-1] = i+1;
	int cur = 0;
	for(auto i : b) {
		//cout << _ << " " << __ << " " << i << endl;
		//cout << i << " ";

		res += ++cur - get(i);
		//cout << i << " " << res << endl;
	}
	return res;
}

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