Submission #525972

#	Time	Username	Problem	Language	Result	Execution time	Memory
525972		Hanksburger	Arranging Shoes (IOI19_shoes)	C++17	50 / 100	39 ms	25748 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
vector<long long> pos1[100005], pos2[100005];
long long a[100005], cnt;
bool b[100005];
long long f(long long l, long long r)
{
	if (l==r)
		return 0;
	long long mid=(l+r)/2, index=(l+r)/2+1;
	long long res=f(l, mid)+f(mid+1, r);
	for (long long i=l; i<=mid; i++)
	{
		while (index<=r && a[i]>a[index])
			index++;
		res+=index-mid-1;
	}
	sort(a+l, a+r+1);
	return res;
}
long long count_swaps(vector<int> v)
{
	for (long long i=0; i<v.size(); i++)
	{
		if (v[i]<0)
			pos1[-v[i]].push_back(i);
		else
			pos2[v[i]].push_back(i);
	}
	for (long long i=1; i<=v.size(); i++)
	{
		reverse(pos1[i].begin(), pos1[i].end());
		reverse(pos2[i].begin(), pos2[i].end());
	}
	for (long long i=0; i<v.size(); i++)
	{
		if (b[i])
			continue;
		if (v[i]<0)
		{
			cnt+=2;
			a[i]=cnt-1;
			a[pos2[-v[i]][pos2[-v[i]].size()-1]]=cnt;
			b[pos2[-v[i]][pos2[-v[i]].size()-1]]=1;
			pos1[-v[i]].pop_back();
			pos2[-v[i]].pop_back();
		}
		else
		{
			cnt+=2;
			a[i]=cnt;
			a[pos1[v[i]][pos1[v[i]].size()-1]]=cnt-1;
			b[pos1[v[i]][pos1[v[i]].size()-1]]=1;
			pos1[v[i]].pop_back();
			pos2[v[i]].pop_back();
		}
	}
	return f(0, cnt-1);
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:23:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |  for (long long i=0; i<v.size(); i++)
      |                      ~^~~~~~~~~
shoes.cpp:30:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |  for (long long i=1; i<=v.size(); i++)
      |                      ~^~~~~~~~~~
shoes.cpp:35:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |  for (long long i=0; i<v.size(); i++)
      |                      ~^~~~~~~~~

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