Submission #433195

#	Time	Username	Problem	Language	Result	Execution time	Memory
433195		kostia244	Arranging Shoes (IOI19_shoes)	C++17	30 / 100	80 ms	6736 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) {
	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;
	};
	ll res = 0;
	map<int, int> tie;
	for(auto &i : s) i = 2*abs(i) + (i>0);
	vector<array<int, 3>> b;
	for(int i = 0; i < 2*n; i++) 
		b.push_back({s[i], tie[s[i]]++, i+1});
	sort(all(b), [&](auto x, auto y) {
		if(x[0]/2 != y[0]/2) return x[0]/2 < y[0]/2;
		if(x[1] != y[1]) return x[1] < y[1];
		return x[0] < y[0];
	});
	int cur = 0;
	for(auto [_, __, i] : b) {
		//cout << _ << " " << __ << " " << i << endl;
		res += ++cur - get(i);
	}
	return res;
}

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