C++ 18352 특정 거리의 도시 찾기 [최단 거리, BFS]

 

코드

#include <iostream>
#include <algorithm>
#include <map>
#include <vector>
#include <queue>


void BFS(int _City,int _Start, int _k,std::map<int, std::vector<int>>& _Map)
{
	std::vector<int> Result;
	std::vector<bool> Visited;

	Visited.resize(_City);
	std::queue<std::pair<int, int>> Q;

	Q.push(std::make_pair(_Start, 0));
	
	Visited[_Start-1] = true;

	while (!Q.empty())
	{
		int Value = Q.front().first;
		int Count = Q.front().second;

		Q.pop();

		if (Count == _k)
		{
			Result.push_back(Value);
		}

		for (int i = 0; i < _Map[Value].size(); i++)
		{
			int Next = _Map[Value][i];

			

			if (false == Visited[Next - 1])
			{
				Visited[Next - 1] = true;
				Q.push(std::make_pair(Next, Count + 1));
			}
		}
	}

	if (Result.size() == 0)
	{
		std::cout << -1 << "\n";
	}
	else
	{

		std::sort(Result.begin(), Result.end());

		for (int i = 0; i < Result.size(); i++)
		{
			std::cout << Result[i] << "\n";
		}
	}
}

int main()
{
	std::map<int, std::vector<int>> Map;

	int N, M, K, X;

	std::cin >> N >> M >> K >> X;

	for (int i = 0; i < M; i++)
	{
		int A, B;

		std::cin >> A >> B;

		Map[A].push_back(B);
	}

	BFS(N,X, K, Map);

	return 0;
}