Submission #810213

#	Time	Username	Problem	Language	Result	Execution time	Memory
810213		Sohsoh84	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	261 ms	25152 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pll;

#define X		first
#define Y		second
#define sep		' '

const int MAXN = 2e6 + 10;

int n, fen[MAXN];
map<int, vector<int>> mp;

inline void update(int ind, int val) {
	for (++ind; ind < MAXN; ind += ind & -ind)
		fen[ind] += val;
}

inline int query(int ind) {
	int ans = 0;
	for (++ind; ind > 0; ind -= ind & -ind)
		ans += fen[ind];
	
	return ans;
}

inline int query(int l, int r) {
	if (r < l) return 0;
	int ans = query(r);
	if (l) ans -= query(l - 1);
	return ans;
}

ll count_swaps(vector<int> vec) {
	ll ans = 0;
	n = vec.size();
	for (int i = n - 1; i >= 0; i--)
		mp[vec[i]].push_back(i);
	
	for (int i = 0; i < n; i++) {
		if (query(i, i)) continue;
		int ind = mp[-vec[i]].back();
		mp[vec[i]].pop_back();
		mp[-vec[i]].pop_back();
	
		if (vec[i] > 0) ans++;
		ans += ind - i - 1 - query(i + 1, ind - 1);
		update(i, 1);
		update(ind, 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