Submission #841610

#	Time	Username	Problem	Language	Result	Execution time	Memory
841610		andrei_c1	Longest Trip (IOI23_longesttrip)	C++17	40 / 100	9 ms	600 KiB

longesttrip

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

using namespace std;

uint64_t randomAddress() {
	char *p = new char;
	delete p;
	return uint64_t(p);
}
uint64_t SEED = chrono::steady_clock::now().time_since_epoch().count() * (randomAddress() | 1);
// mt19937 rng(SEED);

void concat(vector<int> &t1, vector<int> &t2) {
	if(t1.size() < t2.size()) {
		swap(t1, t2);
	}
	while(!t2.empty()) {
		t1.emplace_back(t2.back());
		t2.pop_back();
	}
}

std::vector<int> longest_trip(int n, int D) {
	srand(SEED);
	vector<int> res, ord(n);
	iota(ord.begin(), ord.end(), 0);
	random_shuffle(ord.begin(), ord.end());
	if(D == 3) {
		for(const auto &u: ord) {
			res.emplace_back(u);
		}
	} else if(D == 2) {
		deque<int> dq;
		dq.emplace_back(ord.back());
		ord.pop_back();
		for(vector<int>::iterator it = ord.begin(); it != ord.end(); it++) {
			if(are_connected({dq.back()}, {*it})) {
				dq.emplace_back(*it);
				ord.erase(it);
				break;
			}
		}
		assert((int) dq.size() == 2);
		for(const auto &u: ord) {
			if(are_connected({u}, {dq.back()})) {
				dq.emplace_back(u);
			} else {
				assert(are_connected({u}, {dq.front()}));
				dq.emplace_front(u);
			}
		}
		for(const auto &u: dq) {
			res.emplace_back(u);
		}
	} else {
		vector<int> t1, t2;
		t1.emplace_back(ord.back());
		ord.pop_back();
		t2.emplace_back(ord.back());
		ord.pop_back();
		for(const auto &u: ord) {
			if(are_connected({u}, {t1.back()})) {
				t1.emplace_back(u);
			} else if(are_connected({u}, {t2.back()})) {
				t2.emplace_back(u);
			} else {
				concat(t1, t2);
				t2.emplace_back(u);
			}
		}
		if(t1.size() < t2.size()) {
			swap(t1, t2);
		}
		for(const auto &u: t1) {
			res.emplace_back(u);
		}
	}
	return res;
}

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