Submission #848926

#	Time	Username	Problem	Language	Result	Execution time	Memory
848926		emad234	Longest Trip (IOI23_longesttrip)	C++17	85 / 100	12 ms	1112 KiB

longesttrip

#include <bits/stdc++.h>
#define all(v) ((v).begin(),(v).end())
#define ll long long
#define F first
#define S second
const ll mod = 1e9 + 7;
const ll mxN = 2e5 + 1;
using namespace std;
bool are_connected(vector<int> A, vector<int> B);
int Search(vector<int>a,vector<int>b){
  if(b.size() == 1) return b[0];
  vector<int>v,v1;
  for(int i = 0;i < b.size() / 2;i++) v.push_back(b[i]);
  for(int i = b.size() / 2;i < b.size();i++) v1.push_back(b[i]);
  if(v.size() && are_connected(a,v)) return Search(a,v);
  else return Search(a,v1);
}
vector<int> longest_trip(int N, int D)
{
  vector<int>v = {0},v1;
  queue<int>q;
  for(int i = 1;i < N;i++)q.push(i);
  while(q.size()){
    int u = q.front();
    q.pop();
    bool x = (v.size() && are_connected({v[v.size() - 1]},{u})),y = (v1.size() &&  are_connected({v1[v1.size() - 1]},{u}));
    if(x && y){
      v.push_back(u);
      reverse(v1.begin(),v1.end());
      for(auto el : v1) v.push_back(el);
      v1.clear();
    }
    else if(x) v.push_back(u);
    else if(y) v1.push_back(u);
    else{
      reverse(v1.begin(),v1.end());
      for(auto el : v1) v.push_back(el);
      v1.clear();
      v1.push_back(u);
    }
  }
  if(v.size() && v1.size() && are_connected(v,v1)){
    if(are_connected({v[0]},{v1[0]})){
      reverse(v.begin(),v.end());
      for(auto x : v1) v.push_back(x);
      return v;
    }
    else if(are_connected({v[v.size() - 1]},{v1[0]})){
      for(auto x : v1) v.push_back(x);
      return v;
    }else if(are_connected({v[0]},{v1[v1.size() - 1]})){
      reverse(v.begin(),v.end());
      reverse(v1.begin(),v1.end());
      for(auto x : v1) v.push_back(x);
      return v;
    }else if(are_connected({v[v.size() - 1]},{v1[v1.size() - 1]})){
      reverse(v1.begin(),v1.end());
      for(auto x : v1) v.push_back(x);
      return v;
    }
    int x = Search(v,v1);
    int y = Search({x},v);
    vector<int>ans;
    int id = 0;
    for(int i = 0;i < v.size();i++){
      if(v[i] == y) id = (i + 1) % v.size();
    }
    int id1;
    int bf;
    for(int i = 0;i < v1.size();i++){
      if(v1[(i + 1) % v1.size()] == x) {
        bf = i;
        id1 = (i + 1) % v1.size();
      }
    }
    while(v[id] != y){
      ans.push_back(v[id]);
      id++;
      id %= v.size();
    }
    ans.push_back(y);
    while(id1 != bf){
      ans.push_back(v1[id1]);
      id1++;
      id1%= v1.size();
    }
    ans.push_back(v1[bf]);
    return ans;
  }else{
    if(v.size() > v1.size()) return v;
    else return v1;
  }
}

Compilation message (stderr)

longesttrip.cpp: In function 'int Search(std::vector<int>, std::vector<int>)':
longesttrip.cpp:13:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |   for(int i = 0;i < b.size() / 2;i++) v.push_back(b[i]);
      |                 ~~^~~~~~~~~~~~~~
longesttrip.cpp:14:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |   for(int i = b.size() / 2;i < b.size();i++) v1.push_back(b[i]);
      |                            ~~^~~~~~~~~~
longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:65:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |     for(int i = 0;i < v.size();i++){
      |                   ~~^~~~~~~~~~
longesttrip.cpp:70:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |     for(int i = 0;i < v1.size();i++){
      |                   ~~^~~~~~~~~~~
longesttrip.cpp:82:15: warning: 'bf' may be used uninitialized in this function [-Wmaybe-uninitialized]
   82 |     while(id1 != bf){
      |           ~~~~^~~~~
longesttrip.cpp:82:15: warning: 'id1' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 45 / 60