Submission #201603

#	Time	Username	Problem	Language	Result	Execution time	Memory
201603		khulegub	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	116 ms	19832 KiB

shoes

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

#define mp make_pair
#define pb push_back
#define xx first
#define yy second
#define ll(x) (x*2) + 1
#define rr(x) (x*2) + 2

using namespace std;

typedef long long i64;


int n;

bool taken[200010];

int ft[200010];

int update(int x){
	x++;
	while (x < n){
		ft[x]++;
		x += x & (-x);
	}
	return 0;
}

int query(int x){
	int ret = 0;
	while (x > 0){
		ret += ft[x];
		x -= x & (-x);
	}
	return ret;
}

int query(int l, int r){
	l++;
	r++;
	return query(r) - query(l - 1);
}

vector<int> lefts[200010], rights[200010];

i64 count_swaps(std::vector<int> s) {

	i64 ans = 0LL;
	n = s.size();

	for (int i = n - 1; i >= 0; i--){
		if (s[i] < 0) lefts[abs(s[i])].pb(i);
		else rights[abs(s[i])].pb(i);
	}

	for (int i = 0; i < n; i++){
		if (!taken[i]){
			taken[i] = true;
			int other;
			if (s[i] < 0){
				other = rights[abs(s[i])].back();

				rights[abs(s[i])].pop_back();
				lefts[abs(s[i])].pop_back();
			}
			else{
				other = lefts[abs(s[i])].back();
				
				rights[abs(s[i])].pop_back();
				lefts[abs(s[i])].pop_back();
				ans++;
			}
			taken[other] = true;

			ans += other - i - 1;

			ans -= query(i + 1, other - 1);

			update(other);
		}
	}
	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