Submission #758991

#	Time	Username	Problem	Language	Result	Execution time	Memory
758991		Trumling	Arranging Shoes (IOI19_shoes)	C++14	50 / 100	1067 ms	33976 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std; 
 
typedef long long ll;
#define pb push_back
#define F first
#define S second
#define enter cout<<'\n';
#define INF 99999999999999999
#define MOD 1000000007
#define all(x) x.begin(),x.end()
 
long long count_swaps(vector<int> s) 
{
	ll nn=s.size();

	map<int,vector<int>>mp;
	for(int i=0;i<nn;i++)
	mp[s[i]].pb(i);

vector<pair<int,pair<int,int>>>g;
vector<int>answ(nn);

for(int j=1;j<=nn;j++)
{
	if(mp[j].empty())
	continue;

	auto x=mp[-j],y=mp[j];

	for(int i=0;i<x.size();i++)
	g.pb({x[i]+y[i]+((x[i]<y[i])?-1:0),{x[i],y[i]}});
}
sort(all(g));

ll idx=1;
for(auto x:g)
{
	answ[x.S.F]=idx++;
	answ[x.S.S]=idx++;
}
ll ans=0;
for(int i=0;i<nn;i++)
	for(int j=0;j<i;j++)
		if(answ[i]<answ[j])
			ans++;

	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:32:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |  for(int i=0;i<x.size();i++)
      |              ~^~~~~~~~~
shoes.cpp:44:1: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   44 | for(int i=0;i<nn;i++)
      | ^~~
shoes.cpp:49:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   49 |  return ans;
      |  ^~~~~~

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