Submission #983522

#	Time	Username	Problem	Language	Result	Execution time	Memory
983522		Faisal_Saqib	Permutation (APIO22_perm)	C++17	10 / 100	1072 ms	464 KiB

perm

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define vll vector<int>
vector<int> cp(ll k)// O(lg n)
{
    vector<int> ans;
    ll n_req=0;
    ll hb=-1;
    for(int j=59;j>=0;j--)
    {
        ll pw=(1ll<<j);
        if(k&pw)
        {
            if(hb==-1)
            {
                n_req+=j;
                hb=j;
            }
            else
                n_req++;
        }
    }
    ll last=n_req-1;
    int first=0;
    // cout<<last<<endl;
    for(int l=0;l<60 and l<hb;l++)
    {
        if(k&(1ll<<l))
        {
            ans.push_back(first);
            first++;
        }
        if(first<=last)
        {
            ans.push_back(last);
            last--;
        }
    }
    reverse(begin(ans),end(ans));
    return ans;
}
ll task(ll n) // O(lg n)
{
    ll cp=0;
    for(int bit=59;bit>=0;bit--)
    {
        if(n&(1ll<<bit))
        {
            cp+=bit;
            n^=(1ll<<bit);
            break;
        }
    }
    while(n)
    {
        cp++;
        n-=(n&-n);
    }
    return cp;
}
const ll SQ=21;
int cpp(ll k)
{
    ll mx=task(k);
    ll a=-1;
    ll b=k;
    for(ll d=2;d<=SQ and d<k;d++)
    {
        if(k%d==0)
        {
            ll f=cpp(d);
            ll s=cpp(k/d);
            if((f+s)<mx)
            {
                mx=f+s;
                a=d;
                b=k/d;
            }
        }
    }
    return mx;
}

vector<int> construct_permutation(ll k)
{
    ll mx=task(k);
    ll a=-1;
    ll b=k;
    for(ll d=2;d<=SQ and d<k;d++)
    {
        if(k%d==0)
        {
            ll f=cpp(d);
            ll s=cpp(k/d);
            if((f+s)<mx)
            {
                mx=f+s;
                a=d;
                b=k/d;
            }
        }
    }
    if(a==-1)
    {
        return cp(k);
    }
    else{
        vll ap=construct_permutation(a);
        vll bp=construct_permutation(b);
        ll nm=ap.size();
        for(auto i:bp)
            ap.pb(i+nm);
        return ap;
    }
    return {};
}

Compilation message (stderr)

perm.cpp: In function 'int cpp(long long int)':
perm.cpp:67:8: warning: variable 'a' set but not used [-Wunused-but-set-variable]
   67 |     ll a=-1;
      |        ^
perm.cpp:68:8: warning: variable 'b' set but not used [-Wunused-but-set-variable]
   68 |     ll b=k;
      |        ^

• Subtask 1: 10 / 10
• Subtask 2: 0 / 90