图的深度遍历

class list_node:
    def __init__(self):
        self.val = 0
        self.next = None


head = [list_node()] * 9  # 声明一个节点类型的链表数组

run = [0] * 9


def dfs(current):  # 深度优先函数
    run[current] = 1
    print('[%d] ' % current, end='')
    ptr = head[current].next
    while ptr != None:
        if run[ptr.val] == 0:  # 如果顶点尚未遍历，
            dfs(ptr.val)  # 就进行dfs的递归调用
        ptr = ptr.next


# 声明图的边线数组
data = [[1, 2], [2, 1], [1, 3], [3, 1], 
        [2, 4], [4, 2], [2, 5], [5, 2], 
        [3, 6], [6, 3], [3, 7], [7, 3], 
        [4, 8], [8, 4], [5, 8], [8, 5], 
        [6, 8], [8, 6], [8, 7], [7, 8]]
for i in range(1, 9):  # 共有八个顶点
    run[i] = 0  # 把所有顶点设置成尚未遍历过
    head[i] = list_node()
    head[i].val = i  # 设置各个链表头的初值
    head[i].next = None
    ptr = head[i]  # 设置指针指向链表头
    for j in range(20):  # 二十条边线
        if data[j][0] == i:  # 如果起点和链表头相等，则把顶点加入链表
            newnode = list_node()
            newnode.val = data[j][1]
            newnode.next = None
            while True:
                ptr.next = newnode  # 加入新节点
                ptr = ptr.next
                if ptr.next == None:
                    break

print('图的邻接表内容：')  # 打印图的邻接表内容
for i in range(1, 9):
    ptr = head[i]
    print('顶点 %d=> ' % i, end='')
    ptr = ptr.next
    while ptr != None:
        print('[%d] ' % ptr.val, end='')
        ptr = ptr.next
    print()
print('深度优先遍历的顶点：')  # 打印深度优先遍历的顶点
dfs(1)
print()