|시간 제한||메모리 제한||제출||정답||맞은 사람||정답 비율|
|1 초||512 MB||119||50||27||42.857%|
Jian-Jia is a young boy who loves playing games. When he is asked a question, he prefers playing games rather than answering directly. Jian-Jia met his friend Mei-Yu and told her about the flight network in Taiwan. There are n cities in Taiwan (numbered 0, ..., n - 1), some of which are connected by flights. Each flight connects two cities and can be taken in both directions.
Mei-Yu asked Jian-Jia whether it is possible to go between any two cities by plane (either directly or indirectly). Jian-Jia did not want to reveal the answer, but instead suggested to play a game. Mei-Yu can ask him questions of the form "Are cities x and y directly connected with a flight?", and Jian-Jia will answer such questions immediately. Mei-Yu will ask about every pair of cities exactly once, giving r = n(n - 1)/2 questions in total. Mei-Yu wins the game if, after obtaining the answers to the first i questions for some i < r, she can infer whether or not it is possible to travel between every pair of cities by flights (either directly or indirectly). Otherwise, that is, if she needs all r questions, then the winner is Jian-Jia.
In order for the game to be more fun for Jian-Jia, the friends agreed that he may forget about the real Taiwanese flight network, and invent the network as the game progresses, choosing his answers based on Mei-Yu's previous questions. Your task is to help Jian-Jia win the game, by deciding how he should answer the questions.
We explain the game rules with three examples. Each example has n = 4 cities and r = 6 rounds of question and answer.
In the first example (the following table), Jian-Jia loses because after round 4, Mei-Yu knows for certain that one can travel between any two cities by flights, no matter how Jian-Jia answers questions 5 or 6.
In the next example Mei-Yu can prove after round 3 that no matter how Jian-Jia answers questions 4, 5, or 6, one cannot travel between cities 0 and 1 by flights, so Jian-Jia loses again.
In the final example Mei-Yu cannot determine whether one can travel between any two cities by flights until allsix questions are answered, so Jian-Jia wins the game. Specifically, because Jian-Jia answered yes to the last question (in the following table), then it is possible to travel between any pair of cities. However, if Jian-Jia had answered no to the last question instead then it would be impossible.
Please write a program that helps Jian-Jia win the game. Note that neither Mei-Yu nor Jian-Jia knows the strategy of each other. Mei-Yu can ask about pairs of cities in any order, and Jian-Jia must answer them immediately without knowing the future questions. You need to implement the following two functions.
void initialize(int n);
initializefirst. The parameter n is the number of cities.
int hasEdge(int u, int v);
hasEdgefor r = n(n -1)/2 times. These calls represent Mei-Yu's questions, in the order that she asks them. You must answer whether there is a direct flight between cities u and v. Specifically, the return value should be 1 if there is a direct flight, or 0 otherwise.
n = 4
4 ≤ n ≤ 80
4 ≤ n ≤ 1500
The sample grader reads the input in the following format:
vthat describe a question regarding cities u and v.
C++17, C++14, C++20, C++14 (Clang), C++17 (Clang), C++20 (Clang)