Submission #980520

#	Time	Username	Problem	Language	Result	Execution time	Memory
980520		Tuanlinh123	Fun Tour (APIO20_fun)	C++17	100 / 100	168 ms	22836 KiB

fun

#include "fun.h"
#include<bits/stdc++.h>
#define ll int
#define pll pair<ll, ll>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define ld long double
#define sz(a) ((ll)(a).size())
using namespace std;
 
const ll maxn=100005;
ll dist(ll a, ll b) {return hoursRequired(a, b);}
ll subcnt(ll a, ll b) {return attractionsBehind(a, b);}
 
vector<int> createFunTour(int n, int Q) 
{
    ll g=0;
    // findcentroid 
    {
        ll cr=n;
        for (ll j=1; j<n; j++)
        {
            ll x=subcnt(0, j);
            if (x*2>=n && x<=cr)
                g=j, cr=x;
        }
    }
    vector <ll> d(n, 0);
    vector <pll> dis;
    vector <vector <pll>> branch;
    for (ll i=0; i<n; i++)
        if (i!=g)
        {
            dis.pb({dist(g, i), i}), d[i]=dis.back().fi;
            if (dis.back().fi==1) branch.pb(vector <pll> {{1, i}}), dis.pop_back();
        } 
    for (auto [d, i]:dis)
        for (ll j=0; j<sz(branch); j++)
        {
            if (j+1==sz(branch)) branch[j].pb({d, i});
            else if (dist(i, branch[j][0].se)+1==d) {branch[j].pb({d, i}); break;}
        }
    for (ll j=0; j<sz(branch); j++) 
        sort(branch[j].begin(), branch[j].end(), greater<pll>());
    ll first=0;
    vector <ll> tour;
    if (sz(branch)==3)
    {
        // case 2
        ll ptr[3]={}, last=-1, fat=0;
        while (1)
        {
            // check
            {
                ll sum=0, ok=1;
                for (ll i=0; i<3; i++) 
                    sum+=sz(branch[i])-ptr[i];
                for (ll i=0; i<3; i++)
                    if ((sz(branch[i])-ptr[i])*2>=sum) fat=i, ok=0;
                if (!ok || !sum) break;
            }
            ll big=-1;
            for (ll i=0; i<3; i++)
                if (i!=last && ptr[i]<sz(branch[i]))
                    if (big==-1 || branch[big][ptr[big]].fi<branch[i][ptr[i]].fi)
                        big=i;
            tour.pb(branch[big][ptr[big]].se), ptr[big]++, last=big;
        }
        vector <pll> b1, b2;
        for (ll i=0; i<3; i++)
        {
            if (i==fat) b1.insert(b1.end(), branch[i].begin()+ptr[i], branch[i].end());
            else b2.insert(b2.end(), branch[i].begin()+ptr[i], branch[i].end());
        }
        sort(b2.begin(), b2.end(), greater<pll>());
        branch[0]=b1, branch[1]=b2;
        if (last==fat) swap(branch[0], branch[1]);
    }
    else if (sz(branch[0])<sz(branch[1])) swap(branch[0], branch[1]);
    if (sz(tour)>=2 && d[tour.back()]<branch[1][0].fi) swap(branch[0], branch[1]);
    for (ll ptr[2]={}, t=0; ptr[0]<sz(branch[0]) || ptr[1]<sz(branch[1]); ptr[t]++, t^=1)
        tour.pb(branch[t][ptr[t]].se);
    tour.pb(g); return tour;
}

Compilation message (stderr)

fun.cpp: In function 'std::vector<int> createFunTour(int, int)':
fun.cpp:47:8: warning: unused variable 'first' [-Wunused-variable]
   47 |     ll first=0;
      |        ^~~~~

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 21 / 21
• Subtask 4: 19 / 19
• Subtask 5: 34 / 34