Submission #841637

#	Time	Username	Problem	Language	Result	Execution time	Memory
841637		Pajaraja	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	11 ms	760 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;
int broj;
pair<int,int> findedge(vector<int> a,vector<int> b)
{
    int l=0,r=b.size()-1;
    while(l!=r)
    {
        int s=(l+r)/2;
        vector<int> q;
        for(int i=l;i<=s;i++) q.push_back(b[i]);
        if(are_connected(a,q)) r=s;
        else l=s+1;
    }
    int ind=l;
    vector<int> d;
    d.push_back(b[l]);
    l=0; r=a.size()-1;
    while(l!=r)
    {
        int s=(l+r)/2;
        vector<int> q;
        for(int i=l;i<=s;i++) q.push_back(a[i]);
        if(are_connected(q,d)) r=s;
        else l=s+1;
    }
    return {l,ind};
}
mt19937 rng(time(0));
bool ask(int a,int b)
{
    broj++;
    vector<int> a1,b1;
    a1.push_back(a);
    b1.push_back(b);
    return are_connected(a1,b1);
}
std::vector<int> longest_trip(int N, int D)
{
    broj=0;
    vector<int> cur1,cur2;
    vector<int> all;
    for(int i=0;i<N;i++) all.push_back(i);
    shuffle(all.begin(),all.end(),rng);
    cur1.push_back(all[0]);
    bool nema=true;
    for(int i=1;i<N;i++)
    {
        int x=all[i];
        if(ask(cur1.back(),x))
        {
            cur1.push_back(x);
            nema=false;
            if(cur2.size()==0) nema=true;
        }
        else
        {
            if(nema) cur2.push_back(x);
            else
            {
                if(!ask(cur2.back(),x))
                {
                    if(cur2.size()==1) nema=true;
                    else if(!ask(cur2[0],x)) nema=true;
                    for(int i=cur2.size()-1;i>=0;i--) cur1.push_back(cur2[i]);
                    cur2.clear();
                    if(nema)  cur2.push_back(x);
                    else cur1.push_back(x);
                    nema=true;
                }
                else
                {
                    cur2.push_back(x);
                    nema=true;
                }
            }
        }
    }
    if(cur1.size()<cur2.size()) swap(cur1,cur2);
    if(cur2.size()==0) return cur1;
    if(!are_connected(cur1,cur2))
    {
        if(cur1.size()<cur2.size()) return cur2;
        return cur1;
    }
    if(cur2.size()==1)
    {
        if(ask(cur1.back(),cur2.back()))
        {
            cur1.push_back(cur2.back());
            return cur1;
        }
        pair<int,int> p=findedge(cur1,cur2);
        vector<int> ans;
        ans.push_back(cur2[0]);
        int c=p.first;
        do{
            ans.push_back(cur1[c]);
            c++;
            c%=cur1.size();
        } while(c!=p.first);
        return ans;
    }
    int al=cur1[0],ar=cur1.back(),bl=cur2[0],br=cur2.back();
    if(are_connected({al,ar},{bl,br}))
    {
        vector<int> ans;
        if(ask(al,bl))
        {
            reverse(cur1.begin(),cur1.end());
            for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
            for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
            return ans;
        }
        if(ask(al,br))
        {
            reverse(cur1.begin(),cur1.end());
            reverse(cur2.begin(),cur2.end());
            for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
            for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
            return ans;
        }
        if(ask(ar,bl))
        {
            for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
            for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
            return ans;
        }
        if(ask(ar,br))
        {
            reverse(cur2.begin(),cur2.end());
            for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
            for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
            return ans;
        }
    }
    pair<int,int> p=findedge(cur1,cur2);
    vector<int> ans;
    int c=p.second;
    do
    {
        c++;
        c%=cur2.size();
        ans.push_back(cur2[c]);
    } while(c!=p.second);
    c=p.first;
    do
    {
        ans.push_back(cur1[c]);
        c++;
        c%=cur1.size();
    } while(c!=p.first);
    return ans;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:112:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  112 |             for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:113:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  113 |             for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:120:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |             for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:121:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |             for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:126:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  126 |             for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:127:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  127 |             for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:133:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  133 |             for(int i=0;i<cur1.size();i++) ans.push_back(cur1[i]);
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:134:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  134 |             for(int i=0;i<cur2.size();i++) ans.push_back(cur2[i]);
      |                         ~^~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 60 / 60