Submission #1064145

#	Time	Username	Problem	Language	Result	Execution time	Memory
1064145		DorostWef	Longest Trip (IOI23_longesttrip)	C++17	85 / 100	16 ms	688 KiB

longesttrip

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

using namespace std;

#define ask are_connected

std::vector<int> longest_trip(int N, int D) {
	int n = N;
	vector <int> A = {0}, B;
	int lst = -1;
	for (int i = 1; i < n; i++) {
		if (B.empty()) {
			lst = 1;
			bool f = ask ({A.back()}, {i});
			if (f)
				A.push_back(i);
			else {
				B.push_back(i);
			}
		} else {
			if (lst == 2 && ask ({A.back()}, {B.back()})) {
				reverse (B.begin(), B.end());
				for (int x : B)
					A.push_back(x);
				B.clear();
				i--;
			} else if (ask ({A.back()}, {i})) {
				A.push_back(i);
			} else {
				B.push_back(i);
			}
			lst = 2;
		}
	}/*
		cout << "A : ";
		for (int x : A)
		cout << x << ' ';
		cout << '\n';
		cout << "B : ";
		for (int y : B)
		cout << y << ' ';
		cout << '\n';*/
	if (B.empty()) {
		return A;
	}
	if (!ask (A, B)) {
		if (A.size() >= B.size()) {
			return A;
		}
		return B;
	}
	if (ask ({A[0]}, {B[0]})) {
		reverse (A.begin(), A.end());
		for (int x : B) {
			A.push_back(x);
		}
		return A;
	} else {
		bool f;
		if (A.size() >= 2) {
			f = ask ({A[0]}, {A.back()});
			if (!f) {
				for (int x : B) {
					A.push_back(x);
				}
				return A;
			}
		} 
		if (B.size() >= 2) {
			f = ask ({B[0]}, {B.back()});
			if (!f) {
				for (int x : A) {
					B.push_back(x);
				}
				return B;
			}
		}
	}
	int l = -1, r = (int)A.size() - 1;
	while (r - l > 1) {
		int mid = (l + r) >> 1;
		vector <int> C;
		for (int i = 0; i <= mid; i++) {
			C.push_back(A[i]);
		}
		if (ask (C, B)) {
			r = mid;
		} else {
			l = mid;
		}
	}
	vector <int> wef = {A[r]};
	int ww1 = r;
	l = -1, r = (int)B.size() - 1;
	while (r - l > 1) {
		int mid = (l + r) >> 1;
		vector <int> C;
		for (int i = 0; i <= mid; i++) {
			C.push_back(B[i]);
		}
		if (ask (C, wef)) {
			r = mid;
		} else {
			l = mid;
		}
	}
	int ww2 = r;
	vector <int> ans;
	for (int i = ww1 + 1; i < (int)A.size(); i++) {
		ans.push_back(A[i]);
	}
	for (int i = 0; i <= ww1; i++) {
		ans.push_back(A[i]);
	}
	for (int i = ww2; i < (int)B.size(); i++) {
		ans.push_back(B[i]);
	}
	for (int i = 0; i < ww2; i++) {
		ans.push_back(B[i]);
	}
	return ans;
}

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