Submission #1029205

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029205		Mr_Husanboy	Longest Trip (IOI23_longesttrip)	C++17	85 / 100	12 ms	856 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define ff first
#define ss second
#define all(a) (a).begin(), (a).end()

template<typename T>
int len(T &a){return a.size();}


int ask(int a, int b){
    return are_connected({a}, {b});
}



vector<int> longest_trip(int n, int d)
{
    deque<int> a = {0}, b = {1};
    for(int i = 2; i < n; i ++){
        if(ask(a.back(), i)){
            a.push_back(i);
        }else if(ask(b.back(), i)){
            b.push_back(i);
        }else{
            for(int i = len(b) - 1; i >= 0; i --) a.push_back(b[i]);
            b = {i};
        }
    }
    if(len(b) > len(a)) swap(a, b);
    vector<int> aa, bb;
    for(auto u : a) aa.push_back(u);
    for(auto u : b) bb.push_back(u);

    if(are_connected(aa, bb) == 0){
        if(len(aa) > len(bb)) return aa;
        return bb;
    }
    vector<int> res;
    if(ask(a[0], b[0])){
        for(int i = len(a) - 1; i >= 0; i --){
            res.push_back(a[i]);
        }
        for(int i = 0; i < len(b); i ++) res.push_back(b[i]);
        return res;
    }   
    if(ask(a[0], b.back())){
        for(auto u : b) res.push_back(u);
        for(int i = 0; i < len(a); i ++) res.push_back(a[i]);
        return res;
    }
    
    if(ask(a.back(), b[0])){
        for(auto u : a) res.push_back(u);
        for(auto u : b) res.push_back(u);
        return res;
    }

    if(ask(a.back(), b.back())){
        for(auto u : a) res.push_back(u);
        for(int i = len(b) - 1; i >= 0; i --)  res.push_back(b[i]);
        return res;
    }
    
    int l = -1, r = len(a);
    while(r - l > 1){
        int m = (l + r) / 2;
        vector<int> sh;
        for(int i = 0; i <= m; i ++) sh.push_back(a[i]);
        if(are_connected(sh, bb)){
            r = m;
        }else l = m;
    }
    int i = r;
    l = -1, r = len(b);
    while(r - l > 1){
        int m = (l + r) / 2;
        vector<int> sh;
        for(int k = 0; k <= m; k ++) sh.push_back(b[k]);
        if(are_connected({a[i]}, sh)){
            r = m;
        }else l = m;
    }

    int j = r;

    for(int k = i + 1; k < len(a); k ++) res.push_back(a[k]);
    for(int k = 0; k <= i; k ++) res.push_back(a[k]);
    for(int k = j; k < len(b); k ++) res.push_back(b[k]);
    for(int k = 0; k < j; k ++) res.push_back(b[k]);
    return res;
}

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