Submission #236809

#	Time	Username	Problem	Language	Result	Execution time	Memory
236809		michao	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	163 ms	38648 KiB

shoes

#include <bits/stdc++.h>
#define ll long long int
#define mp make_pair
#define pb push_back
#define ld long double
#define pii pair<int,int>
#define sz(x) (int)x.size()
#define piii pair<pii,pii>
#define precise cout<<fixed<<setprecision(10)
#define st first
#define nd second
#define ins insert
#define vi vector<int>
#define BOOST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
using namespace std;
const int MAX=1<<18;
bool got[MAX*2];
int t[MAX*2];
set<int>a[MAX],b[MAX];
void update(int u,int c)
{
	for (t[u+=MAX]=c;u>1;u>>=1)
		t[u>>1]=t[u]+t[u^1];
}

int query(int u,int v)
{
	int sum=0;
	for (u+=MAX,v+=MAX+1;u<v;u>>=1,v>>=1)
	{
		if (u&1)sum+=t[u++];
		if (v&1)sum+=t[--v];
	}
	return sum;
}

ll count_swaps(vi tab2)
{
	ll ans=0;
	int n=sz(tab2);
	int tab[n+1];
	for (int i=0;i<=n;i++)tab[i]=0;
	for (int i=1;i<=n;i++)tab[i]=tab2[i-1];
	for (int i=1;i<=n;i++)
	{
		if (tab[i]<0)b[-tab[i]].ins(i);
		else a[tab[i]].ins(i);
	}
	for (int i=1;i<=n;i++)update(i,1);
	for (int i=1;i<=n;i++)
	{
		if (got[i])continue;
		got[i]=true;
		if (tab[i]>0)
		{
			int wsk=*b[tab[i]].lower_bound(i);
			b[tab[i]].erase(wsk);
			got[wsk]=true;
			ans+=query(i+1,wsk);
			update(wsk,0);
		}
		else
		{
			int wsk=*a[-tab[i]].lower_bound(i);
			a[-tab[i]].erase(wsk);
			got[wsk]=true;
			ans+=query(i+1,wsk)-1;
			update(wsk,0);
		}
	}
	return ans;
}
/*
int main()
{
	cout<<count_swaps({2, 1, -1, -2});
}
*/

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