Submission #967551

#	Time	Username	Problem	Language	Result	Execution time	Memory
967551		Jarif_Rahman	Longest Trip (IOI23_longesttrip)	C++17	70 / 100	17 ms	960 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

vector<int> longest_trip(int n, int D){
    vector<int> A = {0}, B = {};
    for(int i = 1; i < n; i++){
        if(B.empty()){
             if(are_connected({A.back()}, {i})) A.push_back(i);
             else if(are_connected({A[0]}, {i})) A.insert(A.begin(), i);
             else B = {i};
        }
        else{
            if(are_connected({A.back()}, {i})) A.push_back(i);
            else if(are_connected({B.back()}, {i})) B.push_back(i);
            else{
                reverse(B.begin(), B.end());
                A.insert(A.end(), B.begin(), B.end());
                B.clear();
                i--;
            }
        }
        if(A.size() < B.size()) swap(A, B);
    }

    int na = A.size(), nb = B.size();
    int ans = nb, x = -1, y = -1;

    for(int i = 0; i < nb; i++){
        if(!are_connected({B[i]}, A)) continue;

        int l = 0, r = na-1;
        while(l < r){
            int m = (l+r)/2;
            vector<int> s;
            for(int j = 0; j <= m; j++) s.push_back(A[j]);
            if(are_connected({B[i]}, s)) r = m;
            else l = m+1;
        }
        if(max(i+1, nb-i)+max(l+1, na-l) > ans){
            ans = max(i+1, nb-i)+max(l+1, na-l), x = l, y = i;
        }

        l = 0, r = na-1;
        while(l < r){
            int m = (l+r+1)/2;
            vector<int> s;
            for(int j = m; j < na; j++) s.push_back(A[j]);
            if(are_connected({B[i]}, s)) l = m;
            else r = m-1;
        }
        if(max(i+1, nb-i)+max(l+1, na-l) > ans){
            ans = max(i+1, nb-i)+max(l+1, na-l), x = l, y = i;
        }
    }

    vector<int> C = A;

    if(x != -1){
        C.clear();
        if(na > 1 && are_connected({A[0]}, {A.back()})){
            for(int i = x+1; i <= na+x; i++) C.push_back(A[i%na]);
        }
        else if(na-x > x+1){
            for(int i = na-1; i >= x; i--) C.push_back(A[i]);
        }
        else{
            for(int i = 0; i <= x; i++) C.push_back(A[i]);
        }

        if(nb > 1 && are_connected({B[0]}, {B.back()})){
            for(int i = y; i < nb+y; i++) C.push_back(B[i%nb]);
        }
        else if(nb-y > y+1){
            for(int i = y; i < nb; i++) C.push_back(B[i]);
        }
        else{
            for(int i = y; i >= 0; i--) C.push_back(B[i]);
        }
    }

    return C;
}

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 30 / 60