Submission #210986

#	Time	Username	Problem	Language	Result	Execution time	Memory
210986		Seanliu	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	789 ms	151968 KiB

shoes

#include "shoes.h"
#include <vector>
#include <deque>
#include <algorithm>
#include <map>
#define int long long int
using namespace std;

inline int Abs(int x){
	return x > 0 ? x : -x;
}

const int maxN = 220226;

map<int, deque<int> > poss;

int bit[maxN], visited[maxN], id[maxN];

void modify(int p){
	for(; p < maxN; p += (p & -p)) bit[p]++;
}

int query(int p){
	int r = 0;
	for(; p; p -= (p & -p)) r += bit[p];
	return r;
}

int count_swaps(std::vector<signed> s) {
	int N = s.size();
	int t, cnt = 0;
	for(int i = 0; i < N; i++){
		visited[i] = false;
		poss[s[i]].push_back(i);
	}
	/*
	for(auto [id, p] : poss){
		cout << id << ": ";
		for(int x : p) cout << x << " ";
		cout << endl;
	}
	*/
	for(int i = 0; i < N; i++){
		//cout << "D" << endl;
		if(visited[i]) continue;	
		t = Abs(s[i]);
		id[poss[-t].front()] = cnt++;
		id[poss[t].front()] = cnt++;	
		visited[poss[t].front()] = true;
		visited[poss[-t].front()] = true;
		poss[t].pop_front();
		poss[-t].pop_front();
	}
	//for(int i = 0; i < N; i++) cout << id[i] << " ";
	//cout << endl;
	int ans = 0;
	for(int i = 0; i < N; i++){
		ans += query(id[i] + 1);		
		modify(id[i] + 2);
	}
	return N * (N - 1) / 2 - 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