Submission #961753

#	Time	Username	Problem	Language	Result	Execution time	Memory
961753		Prieved1	Longest Trip (IOI23_longesttrip)	C++17	15 / 100	36 ms	3952 KiB

longesttrip

    #include "longesttrip.h"
    #include <bits/stdc++.h>
    using namespace std;
    int cnt=0;
    int n;
    map<int, map<int,int>> mp;
    bool query1(int a, int b) {
      if(mp[a][b]!=0)return mp[a][b]-1;
      int c=are_connected({a}, {b});
      mp[a][b]=c+1;
      mp[b][a]=c+1;
      cnt++;
      return c;
    }
    bool query2(int a, int b) {
     for(int j  = 0;j<n;j++) {
      if(a==j or j==b)continue;
      if(mp[a][j]==1 and mp[j][b]==1) {
        mp[a][b]=2;
        mp[b][a]=2;
        return 1;
      }
     }
     return query1(a,b);
    }
    vector<int> longest_trip(int N, int D)
    {
      n=N;
      cnt=0;
      mp.clear();
      srand(time(NULL));
      vector<int> id(N);
      iota(id.begin(), id.end(), 0);
      random_shuffle(id.begin(), id.end());
      vector<int> t[2];
      t[0].push_back(id[0]);
      t[1].push_back(id[1]);
      bool connected=1;
      for(int ii = 2;ii<N;ii++) {
        int i=id[ii];
        if(t[0].size() < t[1].size())swap(t[0], t[1]);
        if(t[1].size()>0 and rand()%2) {
          swap(t[0], t[1]);
        }
        if(query2(i, t[0].back())) {
          t[0].push_back(i);
          connected=1;
        }
        else if(connected==false or query2(i, t[1].back())) {
          t[1].push_back(i);
          connected=false;
        }
        else {
          connected=0;
          while(t[1].size()) {
            t[0].push_back(t[1].back());
            t[1].pop_back();
          }
          t[1].push_back(i);
        }
      }
      assert(cnt<380);
      if(t[0].size()<t[1].size())swap(t[0], t[1]);
      if(t[1].size()==0)return t[0];
      if(query2(t[0][0], t[1].back())) {
        reverse(t[0].begin(), t[0].end());
        while(t[1].size()) {
          t[0].push_back(t[1].back());
          t[1].pop_back();
        }
        return t[0];
      }
      if(query2(t[0][0], t[1][0])) {
        reverse(t[0].begin(), t[0].end());
        reverse(t[1].begin(), t[1].end());
        while(t[1].size()) {
          t[0].push_back(t[1].back());
          t[1].pop_back();
        }
        return t[0];
      }
      if(query2(t[0].back(), t[1][0])) {
        reverse(t[1].begin(), t[1].end());
        while(t[1].size()) {
          t[0].push_back(t[1].back());
          t[1].pop_back();
        }
        return t[0];
      }
      if(are_connected(t[0], t[1])==false)return t[0];
      int lo = 0, hi = t[0].size()-1;
      int res=hi;
      while(lo <= hi) {
        int mid=(lo+hi)/2;
        vector<int> tmp;
        for(int j = 0;j<=mid;j++)tmp.push_back(t[0][j]);
        if(are_connected(tmp, t[1])) {
          res=mid;
          hi=mid-1;
        }
        else{
          lo=mid+1;
        }
      }
      lo=0, hi=t[1].size()-1;
      int res2=hi;
      while(lo <= hi) {
        int mid=(lo+hi)/2;
        vector<int> tmp;
        for(int j = 0;j<=mid;j++)tmp.push_back(t[1][j]);
        if(are_connected(tmp, {t[0][res]})) {
          res2=mid;
          hi=mid-1;
        }
        else{
          lo=mid+1;
        }
      }
      vector<int> ans;
      for(int j = res+1;j<t[0].size();j++) {
        ans.push_back(t[0][j]);
      }
      for(int j = 0;j<=res;j++)ans.push_back(t[0][j]);
      for(int j = res2;j<t[1].size();j++)ans.push_back(t[1][j]);
      for(int j = 0;j<res2;j++)ans.push_back(t[1][j]);
      return ans;
    }

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
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 j = res+1;j<t[0].size();j++) {
      |                         ~^~~~~~~~~~~~
longesttrip.cpp:124:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  124 |       for(int j = res2;j<t[1].size();j++)ans.push_back(t[1][j]);
      |                        ~^~~~~~~~~~~~

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