Graph-BFS-图的广度优先遍历

#include <iostream>
#include <queue>

using namespace std;

/*
5 5
1 2
1 3
1 5
2 4
3 5
1 2 3 5 4
--------------------------------
Process exited with return value 0
Press any key to continue . . .
*/

int sum = 1;
int vertx, edge;
int Graph[20][20] = {0}, book[20] = {0};

void BFS()
{
	//队列
	queue<int> qgraph;

	//标记第一个元素已经访问，并压入队列中。
	book[1] = 1;
	qgraph.push(1);

	//当队列不为空时
	while(!qgraph.empty())
	{
		int x = qgraph.front();
		for(int i = 1; i <= vertx; i++)
		{
			if(Graph[x][i] == 1 && book[i] == 0)
			{
				sum++;
				book[i] = 1;
				qgraph.push(i);
			}
		}

		cout << qgraph.front() << " ";
		qgraph.pop();
	}

	return;
}

int main()
{
	cin >> vertx >> edge;

	for(int i = 1; i <= vertx; i++)
	{
		for(int j = 1; j <= vertx; j++)
		{
			if(i == j) Graph[i][j] = 0;
			Graph[i][j] = 999999;
		}
	}

	for(int i = 1; i <= edge; i++)
	{
		int x, y;
		cin >> x >> y;
		Graph[x][y] = 1;
		Graph[y][x] = 1;
	}

	BFS();

	return 0;
}