Submission #836274

#	Time	Username	Problem	Language	Result	Execution time	Memory
836274		Antekb	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	65 ms	15180 KiB

shoes

#include<bits/stdc++.h>
#include "shoes.h"
#define st first
#define nd second
#define pb push_back
#define eb emplace_back
#define pp pop_back
#define mp make_pair
#define all(x) (x).begin(), (x).end()
using namespace std;
using pii = pair<int, int>;
using vi = vector<int>;
using vii = vector<pii>;
using ll = long long;

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

void debug(){cerr<<"\n";}
template<typename H, typename... T>
void debug(H h, T... t){
	cerr<<h;
	if(sizeof...(t))cerr<<", ";
	debug(t...);
}
#define deb(x...) cerr<<#x<<" = ";debug(x);

const int N=2e5+5;
int tab[N+N];
void add(int v, int c){
	for(v+=N; v; v>>=1){
		tab[v]+=c;
	}
}
int sum(int l, int r){
	int ans=0;
	for(l+=N, r+=N; l<r; l>>=1, r>>=1){
		if(l&1)ans+=tab[l++];
		if(r&1)ans+=tab[--r];
	}
	return ans;
}
ll count_swaps(std::vector<int> s) {
	int n=s.size()/2;
	vector<vi> L(n), R(n);
	for(int i=0; i<n+n; i++){
		if(s[i]>0)L[s[i]-1].pb(i);
		else R[-1-s[i]].pb(i);
		add(i, 1);
	}
	for(int i=0; i<n; i++){
		reverse(all(R[i]));
		reverse(all(L[i]));
	}
	ll ans=0;
	for(int i=0; i<n+n; i++){
		if(tab[N+i]){
			int t=abs(s[i])-1;
			if(s[i]>0)ans++;
			int k=max(L[t].back(), R[t].back());
			add(k, -1);
			ans+=sum(i+1,k);
			L[t].pp();
			R[t].pp();
		}
	}
	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