C语言数据结构与算法之图的遍历(二)

#include <stdio.h>
int main()
{
    int i, j, m, a, b, cur,n, book[101] = { 0 }, e[101][101];
    int que[10001], head, tail;
    scanf("%d %d", &n, &m);
    //初始化二维矩阵
    for (i = 1; i <= n; i++)
        for (j = 1; j <= n; j++)
            if (i == j) e[i][j] = 0;
            else e[i][j] = 99999999;	//我们假设99999999为x
 
    //读入顶点之间的边
    for (i = 1; i <= n; i++)
    {
        scanf("%d %d", &a, &b);
        e[a][b] = 1;
        e[b][a] = 1;	//因为该图为无向图
    }
 
    //队列初始化
    head = 1;
    tail = 1;
 
    //从1号顶点出发，将1号顶点加入队列
    que[tail] = 1;
    tail++;
    book[1] = 1;//标记1号顶点已经入列
 
    //当队列不为空时循环
    while (head < tail && tail <= n)
    {
        cur = que[head];  //当前正在访问的顶点编号
        for (i = 1; i <= n; i++)
        {
            //判断从顶点cur到顶点i是否有边，并判断顶点i是否访问过
            if (e[cur][i] == 1 && book[i] == 0)
            {
                //如果从顶点cur到顶点i右边，且顶点i没有被访问过，将顶点i入列
                que[tail] = i;
                tail++;
                book[i] = 1; //标记表示已经访问过
 
            }
            if (tail > n)  //表示所有点都已经访问过
                break;
        }
 
        head++;
        //注意这个地方，不要忘记head++后，才能继续向下拓展
    }
 
    for (i = 1; i < tail; i++)
        printf("%d",que[i]);
 
 
}