Submission #144031

#	Time	Username	Problem	Language	Result	Execution time	Memory
144031		davitmarg	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	194 ms	20356 KiB

shoes

/*DavitMarg*/
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <stack>
#include <cassert>
#include <iterator>
#include <bitset>
#include <fstream>
#define mod 1000000007ll
#define LL long long
#define LD long double
#define MP make_pair
#define PB push_back
#define all(v) v.begin(),v.end()
using namespace std;

LL ans,ANS;
int n,id=1,used[200005];
vector<int> a,dr[200005],bc[200005];

void mergeSerge(int l,int r)
{
    if(l>=r)
        return;
    int m=(l+r)/2;

    mergeSerge(l,m);
    mergeSerge(m+1,r);
    vector<int> x,y;

    for(int i=l;i<=m;i++)
        x.PB(a[i]);
    for(int i=m+1;i<=r;i++)
        y.PB(a[i]);

    int d=l;
    int p=0,k=0;
    while(p<x.size())
    {
        while(k<y.size() && y[k]<x[p])
        {
            ans+=(LL)(x.size()-p);
            a[d++]=y[k++];
        }
        a[d++]=x[p++];
    }
    while(k<y.size())
        a[d++]=y[k++];

}

LL count_swaps(vector<int> A)
{
    a=A;
    n=A.size()/2;
    for(int i=0;i<a.size();i++)
    {
        if(a[i]>0)
            dr[a[i]].PB(i);
		else
            bc[-a[i]].PB(i);
    }
    for(int i=1;i<=n;i++)
	{
       reverse(all(dr[i]));
       reverse(all(bc[i]));
	}
    for(int i=0;i<a.size();i++)
        if(!used[i])
        {
			int val=abs(a[i]);
			if(a[i]<0)
			{
				used[i]=1;
				used[dr[val].back()]=1;
				a[i]=id++;
				a[dr[val].back()]=id++;
			}
			else
			{
				used[i]=1;
				used[bc[val].back()]=1;
				a[bc[val].back()]=id++;
				a[i]=id++;
			}
				dr[val].pop_back();
				bc[val].pop_back();
        }
    // for(int i=0;i<a.size();i++)
    // cout<<a[i]<<":";
    // cout<<endl;

    mergeSerge(0,2*n-1);
    return ans;
}

//#define death

#ifdef death

int main()
{
    int N;
    cin>>N;
    N*=2;
    vector<int> X;
    for(int i=0;i<N;i++)
    {
		int val=rand()%(N/2)+1;
        cin>>val;
        X.PB(val);
       // X.PB(-val);
    }
	//random_shuffle(all(X));
    cout<<count_swaps(X)<<endl;
	return 0;
}

#endif // death

/*



3
-2 2 2 -2 -2 2


*/

Compilation message (stderr)

shoes.cpp: In function 'void mergeSerge(int, int)':
shoes.cpp:46:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(p<x.size())
           ~^~~~~~~~~
shoes.cpp:48:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while(k<y.size() && y[k]<x[p])
               ~^~~~~~~~~
shoes.cpp:55:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(k<y.size())
           ~^~~~~~~~~
shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:64:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<a.size();i++)
                 ~^~~~~~~~~
shoes.cpp:76:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<a.size();i++)
                 ~^~~~~~~~~

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