Submission #1061322

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061322		noyancanturk	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	12 ms	600 KiB

longesttrip

#include "longesttrip.h"

#include <bits/stdc++.h>
using namespace std;

#define pb push_back

int n,d;

vector<int>getslice(int l,int r,deque<int>&v){
  vector<int>res;
  for(int i=l;i<=r;i++){
    res.pb(v[i]);
  }
  return res;
}

vector<int>longest_trip(int N,int D){
  n=N,d=D;
  deque<int>trip1,trip2;
  trip1.pb(0);
  bool side=0;
  for(int i=1;i<n;i++){
    bool ok=are_connected({trip1.back()},{i});
    if(ok){
      trip1.pb(i);
      side=0;
    }else if(!trip2.size()||side){
      trip2.pb(i);
      side=1;
    }else{
      ok=are_connected({trip2.back()},{i});
      if(ok){
        trip2.pb(i);
        side=1;
      }else{
        while(trip2.size()){
          trip1.pb(trip2.back());
          trip2.pop_back();
        }
        trip2.pb(i);
      }
    }
  }
  if(!trip2.size())return vector<int>(trip1.begin(),trip1.end());
  if(!are_connected(vector<int>(trip1.begin(),trip1.end()),vector<int>(trip2.begin(),trip2.end()))){
    if(trip1.size()<trip2.size())swap(trip1,trip2);
    return vector<int>(trip1.begin(),trip1.end());
  }
  if(are_connected({trip1.front()},{trip2.front()})){
    vector<int>ans;
    for(int i=trip1.size()-1;0<=i;i--){
      ans.pb(trip1[i]);
    }
    for(int i:trip2){
      ans.pb(i);
    }
    return ans;
  }
  if(are_connected({trip1.back()},{trip2.front()})){
    vector<int>ans;
    for(int i:trip1){
      ans.pb(i);
    }
    for(int i:trip2){
      ans.pb(i);
    }
    return ans;
  }
  if(are_connected({trip1.back()},{trip2.back()})){
    vector<int>ans;
    for(int i:trip1){
      ans.pb(i);
    }
    for(int i=trip2.size()-1;0<=i;i--){
      ans.pb(trip2[i]);
    }
    return ans;
  }
  int ans1=0;
  {
    int l=1,r=trip1.size()-1;
    while(l<=r){
      int mid=(l+r)>>1;
      bool ok=are_connected(getslice(l,mid,trip1),vector<int>(trip2.begin(),trip2.end()));
      if(ok){
        ans1=mid;
        r=mid-1;
      }else{
        l=mid+1;
      }
    }
  }
  int ans2=0;
  {
    int l=1,r=trip2.size()-1;
    while(l<=r){
      int mid=(l+r)>>1;
      bool ok=are_connected(getslice(l,mid,trip2),{trip1[ans1]});
      if(ok){
        ans2=mid;
        r=mid-1;
      }else{
        l=mid+1;
      }
    }
  }
  vector<int>ans;
  for(int i=ans1+1;i<trip1.size();i++){
    ans.pb(trip1[i]);
  }
  for(int i=0;i<=ans1;i++){
    ans.pb(trip1[i]);
  }
  for(int i=ans2;i<trip2.size();i++){
    ans.pb(trip2[i]);
  }
  for(int i=0;i<ans2;i++){
    ans.pb(trip2[i]);
  }
  return ans;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:109:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |   for(int i=ans1+1;i<trip1.size();i++){
      |                    ~^~~~~~~~~~~~~
longesttrip.cpp:115:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  115 |   for(int i=ans2;i<trip2.size();i++){
      |                  ~^~~~~~~~~~~~~

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