Submission #962690

#	Time	Username	Problem	Language	Result	Execution time	Memory
962690		Warinchai	Longest Trip (IOI23_longesttrip)	C++17	15 / 100	50 ms	696 KiB

longesttrip

#include "longesttrip.h"
#include<bits/stdc++.h>
using namespace std;
vector<int>longest_trip_3(int N){
    vector<int>ans;
    for(int i=0;i<N;i++)ans.push_back(i);
    return ans;
}
vector<int>longest_trip_2(int N){
    vector<int>ans;
    vector<int>tans;
    tans.push_back(0);
    for(int i=1;i<N;i++){
        if(are_connected({i-1},{i}))tans.push_back(i);
        else if(i!=N-1)tans.push_back(i+1),tans.push_back(i),i++;
        else ans.push_back(i);
    }
    for(auto x:tans)ans.push_back(x);
    return ans;
}
int vis[256];
int fnext(int x,int sz){
    if(sz==0)return -1;
    //cerr<<"fnext:"<<x<<" "<<sz<<"\n";
    int st=1,en=sz,ans=0;
    int id=-1;
    vector<int>ask;
    while(st<=en){
        int m=(st+en)/2;
        ask.clear();
        int cur=0;
        while(ask.size()<m){
            if(!vis[cur])ask.push_back(cur);
            cur++;
        }
        //cerr<<m<<" ask:";
        //for(auto x:ask)cerr<<x<<" ";
        //cerr<<"\n";
        if(are_connected({x},ask)){
            en=m-1;
            ans=m;
            id=cur-1;
        }else{
            st=m+1;
        }
    }
    return id;
}
pair<int,int> fincom(int x,vector<int>ans){
    int sz=ans.size();
    //cerr<<"fnext:"<<x<<" "<<sz<<"\n";
    int st=0,en=sz-1;
    int id=-1,pos=-1;
    vector<int>ask;
    while(st<=en){
        int m=(st+en)/2;
        ask.clear();
        for(int i=0;i<=m;i++)ask.push_back(ans[i]);
        if(are_connected({x},ask)){
            en=m-1;
            id=ans[m];
            pos=m;
        }else{
            st=m+1;
        }
    }
    return {id,pos};
}
vector<int>longest_trip_1(int N){
    for(int i=0;i<256;i++)vis[i]=0;
    vector<int>ans;
    vector<int>rans;
    vector<int>ians;
    ans.push_back(0);
    vis[0]=1;
    int cur=0,left=N-1;
    while(1){
        //cerr<<cur<<"\n";
        int x=fnext(cur,left);
        if(x!=-1){
            cur=x;
            left--;
            ans.push_back(cur);
            vis[cur]++;
        }else{
            break;
        }
    }
    for(int i=0;i<N;i++)if(!vis[i])ians.push_back(i);
    if(ans.size()==N){
        //assert(0);
        return ans;
    }
    int outcom=-1;
    for(int i=0;i<N;i++){
        if(!vis[i]){
            outcom=i;
            break;
        }
    }
    auto x=fincom(outcom,ans);
    int check=are_connected(ans,ians);
    if(!check){
        assert(0);
        return ans.size()>ians.size()?ans:ians;
    }
    for(int i=0;i<=x.second;i++)rans.push_back(ans[i]);
    for(int i=0;i<N;i++)if(!vis[i])rans.push_back(i);
    for(int i=x.second+1;i<ans.size();i++)rans.push_back(ans[i]);
    assert(rans.size()>=ans.size());
    for(int i=1;i<rans.size();i++)assert(are_connected({rans[i]},{rans[i-1]}));
    return rans;
}
vector<int> longest_trip(int N, int D)
{
    if(D==1)return longest_trip_1(N);
    else if(D==2)return longest_trip_2(N);
    else return longest_trip_3(N);
    //cerr<<"end of query\n";
    return {};
}

Compilation message (stderr)

longesttrip.cpp: In function 'int fnext(int, int)':
longesttrip.cpp:32:25: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   32 |         while(ask.size()<m){
      |               ~~~~~~~~~~^~
longesttrip.cpp:25:20: warning: variable 'ans' set but not used [-Wunused-but-set-variable]
   25 |     int st=1,en=sz,ans=0;
      |                    ^~~
longesttrip.cpp: In function 'std::vector<int> longest_trip_1(int)':
longesttrip.cpp:90:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   90 |     if(ans.size()==N){
      |        ~~~~~~~~~~^~~
longesttrip.cpp:109:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |     for(int i=x.second+1;i<ans.size();i++)rans.push_back(ans[i]);
      |                          ~^~~~~~~~~~~
longesttrip.cpp:111:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  111 |     for(int i=1;i<rans.size();i++)assert(are_connected({rans[i]},{rans[i-1]}));
      |                 ~^~~~~~~~~~~~

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