Submission #799495

#	Time	Username	Problem	Language	Result	Execution time	Memory
799495		ZeroCool	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	286 ms	27368 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
#define ll long long
 
using namespace std;
 
const int mxn = 200020;
 
struct FenwickTree{
	ll bit[mxn];
 
	FenwickTree(){
		memset(bit,0,sizeof(bit));	
	}
 
	void add(int pos){
		for(int i = pos;i<mxn;i += i&(-i))bit[i]++;
	}
	ll query(int pos){
		ll ans = 0;
		for(int i = pos;i;i-=i&(-i))ans+=bit[i];
		return ans;
 
	}
};
 
ll count_swaps(vector<int> s) {
	int n = s.size();
 
	map<int,vector<int> > mp;
	for(int i = 0;i<n;i++){
		mp[s[i]].push_back(i);
	}
	for(auto &i : mp)reverse(i.second.begin(),i.second.end());
	int d[n];
	for(int i = 0;i<n;i++)d[i] = 0;
	int cur = 1;
 
	for(int i = 0;i<n;i++){
		if(d[i])continue;
		if(s[i] < 0){
			mp[s[i]].pop_back();
			d[i] = cur;
			d[mp[-s[i]].back()] = cur + 1;
			mp[-s[i]].pop_back();
		}else{
			mp[s[i]].pop_back();
            d[i]=cur+1;
            d[mp[-s[i]].back()]=cur;
            mp[-s[i]].pop_back();
		}
		cur+= 2;
	}
	ll ans = 0;
	FenwickTree fwt;
 
	for(int i = n-1;i>=0;i--){
		ans += fwt.query(d[i] -1 );
		fwt.add(d[i]);
	}
 
	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