Submission #1271628

#	Time	Username	Problem	Language	Result	Execution time	Memory
1271628		david_g611	Arranging Shoes (IOI19_shoes)	C++20	50 / 100	68 ms	22132 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"

using namespace std;

unordered_map<int, vector<int>> ap;

const int NMAX=2e5;

struct Fenwick
{
    int a[NMAX+11];
    Fenwick()
    {
        for(auto &x:a)x=0;
    }
    void update(int poz, int val)
    {
        for(; poz<=NMAX+10; poz+=poz&(-poz))
            a[poz]+=val;
    }
    int query(int poz)
    {
        int suma=0;
        for(; poz>0; poz-=poz&(-poz))
            suma+=a[poz];
        return suma;
    }

}aib;

long long count_swaps(vector<int> S)
{
    int n=S.size();
    int v[n+1];
    bool folosit[n+1];
    for(auto &x:folosit)x=false;
    for(int i=0; i<n; i++)
    {
        v[i+1]=S[i];
        ap[v[i+1]].push_back(i+1);
    }
    for(auto [x, y]:ap)
       reverse(ap[x].begin(), ap[x].end());///ca se le iau cu pop back

    int ans=0;
    for(int i=1; i<=n; i++)
    {
        if(!folosit[i])
        {
            int nxt = ap[-v[i]].back();
            ap[-v[i]].pop_back();
            folosit[nxt]=true;

            ans+=(nxt+aib.query(nxt))-(i+aib.query(i))-1;
            if(v[i]>0)ans++;

            aib.update(i, 1);
            aib.update(nxt, -1);
            ap[v[i]].pop_back();
        }

    }
    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