Submission #313013

#	Time	Username	Problem	Language	Result	Execution time	Memory
313013		hackermub	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	211 ms	141424 KiB

shoes

#include<bits/stdc++.h>
#include "shoes.h"
using namespace std;

#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
#define all(v) v.begin(),v.end()
#define sz(v) (int)v.size()
#define uid uniform_int_distribution<int>
//mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MOD = 1e9+7;
const int64_t INF = 1e18;

const int MAXN = 2e5+7;
int N;
vector<ll> tree(MAXN);

void update(int idx,int val=1){
	while(idx<=N){
		tree[idx]+=val;
		idx+=idx&(-idx);
	}
}

ll read(int idx){
	ll sum=0;
	while(idx>0){
		sum+=tree[idx];
		idx-=idx&(-idx);
	}
	return sum;
}

ll query(int L,int R){
	return read(R)-read(L-1);
}

long long count_swaps(std::vector<int> s) {
	N=s.size();
	int n=N/2;
	queue<int> idx[2*n+1];
	for(int i=0;i<2*n;i++){
		//cout<<s[i]+n<<" ";
		idx[s[i]+n].push(i+1);
	}
	vector<int> perm;
	vector<bool> vis(2*n+1);
	for(int i=0;i<2*n;i++)if(!vis[i]){
		if(s[i]<0){
			perm.pb(i+1); vis[i]=1;
			perm.pb(idx[-s[i]+n].front()); idx[-s[i]+n].pop();
			vis[perm.back()-1]=1;
		}else{
			perm.pb(idx[-s[i]+n].front()); idx[-s[i]+n].pop();
			vis[perm.back()-1]=1;
			perm.pb(i+1); vis[i]=1;
		}
		idx[s[i]+n].pop();
	}
	ll ans=0;
	for(auto x:perm){
		ans+=query(x+1,N);
		update(x);
	}
	return ans;
}

#ifdef OFFLINE

int32_t main(){
    ios_base::sync_with_stdio(false);cin.tie();
    //If you hack my code , You are gay
   	int n;
   	cin>>n;
   	vector<int> s(2*n);
   	for(int i=0;i<2*n;i++){
   		cin>>s[i];
   	}
   	cout<<count_swaps(s);
    return 0;
}

#endif

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