Submission #530471

#	Time	Username	Problem	Language	Result	Execution time	Memory
530471		jamezzz	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	126 ms	139940 KiB

shoes

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

int n,m[200005],ft[200005],o=100000;
vector<pair<int,int>> v;
queue<int> q[200005];

void up(int x,int v){
	while(x<=n){
		ft[x]+=v,x+=x&-x;
	}
}

int qry(int x){
	int res=0;
	while(x)res+=ft[x],x-=x&-x;
	return res;
}

long long count_swaps(vector<int> s){
	n=(int)s.size();
	long long ans=0;
	for(int i=0;i<n;++i){
		if(q[o-s[i]].empty())q[o+s[i]].push(i);
		else{
			int j=q[o-s[i]].front();
			q[o-s[i]].pop();
			v.push_back({j+1,i+1});
			if(s[i]<0)++ans;
		}
	}
	sort(v.begin(),v.end());
	for(int i=n/2-1;i>=0;--i){
		ans+=qry(v[i].second)-qry(v[i].first-1);
		up(v[i].first,1);up(v[i].second,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