Submission #859120

#	Time	Username	Problem	Language	Result	Execution time	Memory
859120		Ludissey	Longest Trip (IOI23_longesttrip)	C++17	85 / 100	10 ms	856 KiB

longesttrip

#include <bits/stdc++.h>
#include "longesttrip.h"
using namespace std;
 
std::vector<int> longest_trip(int n, int d)
{
    vector<int> A;
    vector<int> B;
    A.push_back(0);
    for (int i = 1; i < n-1; i+=2)
    {
        if(are_connected({i},{i+1})){
            if(are_connected({i}, {A.back()})){
                A.push_back(i);
                A.push_back(i+1);
            } 
            else if(B.size()==0 || are_connected({i}, {B.back()})){
                B.push_back(i);
                B.push_back(i+1);
            } 
            else {
                for (int x = B.size()-1; x >= 0; x--) A.push_back(B[x]);
                B.clear();
                B.push_back(i);
                B.push_back(i+1);
            }
        }else{
            if(are_connected({i}, {A.back()})){
                A.push_back(i);
                if(B.size()==0 || are_connected({i}, {B.back()})){
                    for (int x = B.size()-1; x >= 0; x--) A.push_back(B[x]);
                    B.clear();
                }
                B.push_back(i+1);
            } 
            else if(B.size()==0 || are_connected({i}, {B.back()})){
                B.push_back(i);
                if(are_connected({i}, {A.back()})){
                    for (int x = A.size()-1; x >= 0; x--) B.push_back(A[x]);
                    A.clear();
                    B.push_back(i+1);
                    swap(A,B);
                }else{
                    A.push_back(i+1);
                }
            } 
            else {
                A.push_back(i+1);
                for (int x = B.size()-1; x >= 0; x--) A.push_back(B[x]);
                B.clear();
                B.push_back(i);
            }
        }
    }
    if(n%2==0){
        int i=n-1;
        if(are_connected({i}, {A.back()})) A.push_back(i);
        else if(B.size()==0 || are_connected({i}, {B.back()})) B.push_back(i);
        else {
            for (int x = B.size()-1; x >= 0; x--) A.push_back(B[x]);
            B.clear();
            B.push_back(i);
        }
    }
    if(A.size()<B.size()) swap(A,B);
    vector<int> outp;
    if(B.size()==0 || !are_connected({A},{B})) return A;
    int aN=A.size(), bN=B.size();
    if(are_connected({A[aN-1]}, {B[bN-1]})){
        for (int i = 0; i < aN; i++) outp.push_back(A[i]);
        for (int i = bN-1; i >= 0; i--) outp.push_back(B[i]);
        // cout << "method1\n";
    }else if(are_connected({A[aN-1]}, {B[0]})){
        for (int i = 0; i < aN; i++) outp.push_back(A[i]);
        for (int i = 0; i < bN; i++) outp.push_back(B[i]);
        //cout << A.size() << " " << B.size() << " method2\n";
    }else if(are_connected({A[0]}, {B[bN-1]})){
        for (int i = aN-1; i >= 0; i--) outp.push_back(A[i]);
        for (int i = bN-1; i >= 0; i--) outp.push_back(B[i]);
        //cout << "method3\n";
    }else if(are_connected({A[0]}, {B[0]})){
        for (int i = aN-1; i >= 0; i--) outp.push_back(A[i]);
        for (int i = 0; i < bN; i++) outp.push_back(B[i]);
        //cout << "method4\n";
    }else{
        int l=0;
        int r=aN-1;
        while(l<r)
        {
            int mid=(l+r)/2;
            vector<int> vec;
            for (int i = l; i <= mid; i++) vec.push_back(A[i]);
            
            if(are_connected(vec, B)){
                r=mid;
            }else{
                l=mid+1;
            }
        }
        int aConnect=l;
        l=0;
        r=bN-1;
        while(l<r)
        {
            int mid=(l+r)/2;
            vector<int> vec;
            for (int i = l; i <= mid; i++) vec.push_back(B[i]);
            
            if(are_connected({A[aConnect]}, vec)){
                r=mid;
            }else{
                l=mid+1;
            }
        }
        int bConnect=l;
        for (int i = aConnect+1; i < aN; i++) outp.push_back(A[i]);
        for (int i = 0; i <= aConnect; i++) outp.push_back(A[i]);
        for (int i = bConnect; i < bN; i++) outp.push_back(B[i]);
        for (int i = 0; i < bConnect; i++) outp.push_back(B[i]);
        //cout << "methodLast\n";
    }
    return outp;
}
//

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