Submission #599219

#	Time	Username	Problem	Language	Result	Execution time	Memory
599219		Summers	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	89 ms	34664 KiB

shoes

#include "shoes.h"
#include<iostream>
#include<vector>
using namespace std;
vector<long long>v[1000000];
long long fen[1000000];
void update(long long pos,long long val)
{
    for(int i=pos;i<=1000000;i+=(i&-i))
    {
        fen[i]+=val;
    }
}
long long sum(long long val)
{
    long long ss=0;
    for(int i=val;i>0;i-=(i&-i))
    {
        ss+=fen[i];
    }
    return ss;
}
bool is[1000000];
long long count_swaps(std::vector<int> s) {

	long long i,j,n,res=0;
	n=s.size()/2;

	for(i=s.size()-1;i>=0;i--)
    {
        v[s[i]+n].push_back(i);
        update(i+1,1);
    }
    for(i=0;i<s.size();i++)
    {
        if(is[i])continue;
        is[i]=1;

        v[s[i]+n].pop_back();

        long long pos=v[-s[i]+n][v[-s[i]+n].size()-1];
        v[-s[i]+n].pop_back();
        is[pos]=1;

        res+=sum(pos)-sum(i+1);

        update(pos+1,-1);

        if(s[i]>0)res++;
    }
    return res;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:34:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |     for(i=0;i<s.size();i++)
      |             ~^~~~~~~~~
shoes.cpp:26:14: warning: unused variable 'j' [-Wunused-variable]
   26 |  long long i,j,n,res=0;
      |              ^

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