Submission #1240763

#	Time	Username	Problem	Language	Result	Execution time	Memory
1240763		SalihSahin	Longest Trip (IOI23_longesttrip)	C++20	0 / 100	8 ms	448 KiB

longesttrip

#include "bits/stdc++.h"
#include "longesttrip.h"
#define pb push_back
using namespace std;

vector<int> longest_trip(int N, int D){
   if(D == 1){
      vector<vector<int> > paths;
      for(int i = 0; i < N; i++){
         paths.pb({i});
      }

      while(paths.size() > 2){
         vector<vector<int> > npaths;

         for(int i = 0; i + 2 < paths.size(); i += 3){
            int a = paths[i][0], b = paths[i+1][0], c = paths[i+2][0];

            bool c1 = are_connected({a}, {b});
            bool c2 = are_connected({a}, {c});
            bool c3 = are_connected({b}, {c});

            if(c1){
               vector<int> v = paths[i];
               reverse(v.begin(), v.end());
               for(auto itr: paths[i+1]) v.pb(itr);
               npaths.pb(v);
               npaths.pb(paths[i+2]);
            }
            else if(c2){
               vector<int> v = paths[i];
               reverse(v.begin(), v.end());
               for(auto itr: paths[i+2]) v.pb(itr);
               npaths.pb(v);
               npaths.pb(paths[i+1]);
            }
            else if(c3){
               vector<int> v = paths[i+1];
               reverse(v.begin(), v.end());
               for(auto itr: paths[i+2]) v.pb(itr);
               npaths.pb(v);
               npaths.pb(paths[i]);
            }
            else{
               abort();
            }
         }

         if(paths.size() % 3 >= 1){
            npaths.pb(paths[paths.size()-1]);
         }
         if(paths.size() % 3 >= 2){
            npaths.pb(paths[paths.size()-2]);
         }

         paths = npaths;
      }

      bool check = are_connected(paths[0], paths[1]);
      if(paths[1].size() > paths[0].size()) swap(paths[0], paths[1]);

      if(!check){
         return paths[0];
      }
      else{
         if(paths[1].size() == 1){
            int a = paths[0][0], b = paths[0].back(), c = paths[1][0];
            bool c1 = are_connected({a}, {b});
            bool c2 = are_connected({b}, {c});
            bool c3 = are_connected({c}, {a});

            if(c3){
               paths[0].pb(c);
               return paths[0];
            }
            if(c2){
               reverse(paths[0].begin(), paths[0].end());
               paths[0].pb(c);
               return paths[0];
            }

            int x = 0;
            for(auto itr: paths[0]){
               if(are_connected({itr}, {c})){
                  x = itr;
                  break;
               }
            }

            vector<int> updpath;
            for(auto itr: paths[0]){
               updpath.pb(itr);
               if(itr == x) break;
            }
            updpath.pb(c);
            reverse(updpath.begin(), updpath.end());
            reverse(paths[0].begin(), paths[0].end());
            for(auto itr: paths[0]){
               if(itr == x) break;
               updpath.pb(itr);
            }
            return paths[0];
         }
         else{
            int a = paths[0][0], b = paths[0].back(), c = paths[1][0], d = paths[1][1];
            bool c1 = are_connected({a}, {b});
            bool c2 = are_connected({b}, {c});
            bool c3 = are_connected({c}, {a});

            if(c2){
               vector<int> v = paths[0];
               for(auto itr: paths[1]) v.pb(itr);
               return v;
            }
            if(c3){
               vector<int> v = paths[0];
               reverse(v.begin(), v.end());
               for(auto itr: paths[1]) v.pb(itr);
               return v;
            }

            bool c4 = are_connected({c}, {d});
            bool c5 = are_connected({a}, {d});
            bool c6 = are_connected({b}, {d});

            if(c5){
               vector<int> v = paths[0];
               reverse(v.begin(), v.end());
               reverse(paths[1].begin(), paths[1].end());
               for(auto itr: paths[1]) v.pb(itr);
               return v;
            }
            if(c6){
               vector<int> v = paths[1];
               reverse(paths[0].begin(), paths[0].end());
               for(auto itr: paths[0]) v.pb(itr);
               return v;
            }

            // şimdi cycle olduğunu biliyoruz

            pair<int, int> p = {-1, -1};
            for(auto itr: paths[0]){
               for(auto itr2: paths[1]){
                  if(are_connected({itr}, {itr2})){
                     p = {itr, itr2};
                     break;
                  }
               }
               if(p.first != -1) break;
            }

            vector<int> ans;
            for(auto itr: paths[0]){
               if(itr == p.first) break;
               ans.pb(itr);
            }
            reverse(ans.begin(), ans.end());
            reverse(paths[0].begin(), paths[0].end());
            for(auto itr: paths[0]){
               ans.pb(itr);
               if(itr == p.first) break;
            } // son eleman p.first
            
            vector<int> ans2;
            for(auto itr: paths[1]){
               if(itr == p.second) break;
               ans2.pb(itr);
            }
            reverse(ans2.begin(), ans2.end());
            reverse(paths[1].begin(), paths[1].end());
            for(auto itr: paths[1]){
               ans2.pb(itr);
               if(itr == p.second) break;
            } // son eleman p.second

            vector<int> v = ans;
            reverse(ans2.begin(), ans2.end());
            for(auto itr: ans2) v.pb(itr);
            return v;
         }
      }
   }

   return {};
}

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