Submission #426759

#	Time	Username	Problem	Language	Result	Execution time	Memory
426759		dreezy	Arranging Shoes (IOI19_shoes)	C++17	10 / 100	1090 ms	2232 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>

using namespace std;
#define ll long long
#define pb push_back
//n = 1 its either 1 or 0
//n = 8 we can brutazo
//all shoes are same, we just need to get all inversion (even is left, odd is right)
//all shoes need to travel n?

//eta ~ 25 minutes

/*full solutions*/
//O(N^2) 
/*
dp[n][i]
//min swaps at position i after considering n pairs? 

*/

/*SUBTASK 1, 3, 4*/

/*
long long count_swaps(vector<int> s) {
	
	ll ans = 0;
	int n = s.size();
	int first = 0;
	for(int i =0; i<n; i++){
		if(s[i] < 0){
			ans += abs(i - first);
			first +=2;
		}
	}
	return ans;
}
*/

/*SUBTASK 2*/
long long count_swaps(vector<int> s) {
	
	ll ans = 1e18;
	int n = s.size();
	vector<int> lefts(n/2);
	int cntleft = 0;
	for(int i =0; i<n; i++){
		if(s[i] < 0){
			lefts[cntleft++] = i;
		}
	}
	
	do{
		
		ll posans = 0;
		vector<bool> available(n, 1);
	
		//for(int i =0; i<n/ 2; i++) cout << lefts[i]<<", "; cout <<endl;
		
		for(int l =0; l<n/2; l++){
			//get first availabe
			int firstright =-1;
			for(int i =0; i<n ;i++){
				if(available[i] and s[i] == -s[lefts[l]]){
					firstright = i;
					available[i] = false;
					break;
				}
			}
			//cout << lefts[l]<<", "<<firstright<<endl;
			posans += abs(lefts[l] - 2 * l) + abs(firstright -( 2 * l + 1));
		}
		
		ans = min(ans, posans/2);
		
	}while(next_permutation(lefts.begin(), lefts.end()));
	
	return ans;
}

/***********/

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15