Submission #583684

#	Time	Username	Problem	Language	Result	Execution time	Memory
583684		joelau	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	116 ms	17800 KiB

shoes

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

long long N, ft[200005];
vector<long long> lst1[100005], lst2[100005];
priority_queue< pair<long long,long long>, vector< pair<long long,long long> >, greater< pair<long long,long long> > > pq;

void update (long long x, long long v) {
	x++;
	while (x <= N*2) ft[x] += v, x += x & -x;
}

long long query (long long x) {
	x++;
	long long ans = 0;
	while (x) ans += ft[x], x -= x & -x;
	return ans;
}

long long count_swaps(vector<int> s) {
	N = s.size()/2;
	memset(ft,0,sizeof(ft));
	for (long long i = 1; i < N*2; ++i) update(i,1);
	for (long long i = 0; i < N*2; ++i) {
		if (s[i] < 0) lst1[-s[i]-1].push_back(i);
		else lst2[s[i]-1].push_back(i);
	}
	for (long long i = 0; i < N; ++i) if (!lst1[i].empty() && !lst2[i].empty()) {
		reverse(lst1[i].begin(),lst1[i].end()), reverse(lst2[i].begin(),lst2[i].end());
		long long val = lst1[i].back() + lst2[i].back();
		if (lst1[i].back() < lst2[i].back()) val--;
		pq.emplace(val,i);
	}
	long long ans = 0;
	for (long long i = 0; i < N; ++i) {
		long long x,n; tie(x,n) = pq.top(); pq.pop();
		long long val = query(lst1[n].back()) + query(lst2[n].back());
		if (lst1[n].back() < lst2[n].back()) val--;
		ans += val;
		update(lst1[n].back(),-1), update(lst2[n].back(),-1);
		lst1[n].pop_back(), lst2[n].pop_back();
		if (!lst1[n].empty() && !lst2[n].empty()) {
			long long val = lst1[n].back() + lst2[n].back();
			if (lst1[n].back() < lst2[n].back()) val--;
			pq.emplace(val,n);
		}
	}
	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