Submission #676173

#	Time	Username	Problem	Language	Result	Execution time	Memory
676173		speedyArda	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	284 ms	284812 KiB

shoes

#include "shoes.h"
#include "bits/stdc++.h"
using namespace std;
using ll = long long;
const int MAXN = 2e5;
vector< vector< queue<int> > > pos(MAXN + 5, {{}, {}});
ll seg[MAXN * 4 + 5];

void update(int v, int tl, int tr, int l, int r, ll val)
{
	if(l > r)
		return;
	if(l == tl && r == tr)
	{
		seg[v] += val;
	} else 
	{
		int tm =  (tl + tr) / 2;
		update(2 * v, tl, tm, l, min(tm, r), val);
		update(2 * v + 1, tm + 1, tr, max(tm + 1, l), r, val);
	}
}

ll get(int v, int tl, int tr, int pos)
{
	if(tl == tr)
		return seg[v];
	int tm = (tl + tr) / 2;
	if(pos <= tm)
		return seg[v] + get(2 * v, tl, tm, pos);
	else
		return seg[v] + get(2 * v + 1, tm + 1, tr, pos);
}

// Moving elements cause some left elements to move right
long long count_swaps(std::vector<int> s) {
	int n = s.size();
	ll ans = 0;
	//ll curr = 0;
	for(int i = 0; i < n; i++)
	{
		if(s[i] < 0)
		{
			if(pos[abs(s[i])][0].size() > 0) // We have a right pair on our left.
			{
				ll temp = pos[abs(s[i])][0].front();
				pos[abs(s[i])][0].pop();
				int prev = temp;
				temp += get(1, 0, 2 * n - 1, temp);
				ans += i - temp; // 0 for reversing the pairs from RL to LR 
				//cout << ans << " " << temp << " " << prev << ' ' << i << "\n";;
				update(1, 0, 2 * n - 1, prev, i, 1);
				//cout << "hm\n";
			} else 
			{
				pos[abs(s[i])][1].push(i);
			}
		} else 
		{
			if(pos[abs(s[i])][1].size() > 0) // We have a left pair on our left.
			{
				ll temp = pos[abs(s[i])][1].front();
				pos[abs(s[i])][1].pop();
				int prev = temp;
				temp += get(1, 0, 2 * n - 1, temp);
				ans += i - temp - 1; // -1 since not decrementing will cause it to have LR -> RL
				update(1, 0, 2 * n - 1, prev, i, 1);
				
			} else 
			{
				pos[abs(s[i])][0].push(i);
			}
		}
		//cout << i << "\n";
		//curr++;
	}
	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