1004 Counting Leaves (Python实现)

A family hierarchy is usually presented by a pedigree tree. Your job is to count those family members who have no child.

Input Specification:

Each input file contains one test case. Each case starts with a line containing 0<N<100, the number of nodes in a tree, and M (<N), the number of non-leaf nodes. Then M lines follow, each in the format:

ID K ID[1] ID[2] ... ID[K]

where ID is a two-digit number representing a given non-leaf node, K is the number of its children, followed by a sequence of two-digit ID's of its children. For the sake of simplicity, let us fix the root ID to be 01.

The input ends with N being 0. That case must NOT be processed.

Output Specification:

For each test case, you are supposed to count those family members who have no child for every seniority level starting from the root. The numbers must be printed in a line, separated by a space, and there must be no extra space at the end of each line.

The sample case represents a tree with only 2 nodes, where 01 is the root and 02 is its only child. Hence on the root 01 level, there is 0 leaf node; and on the next level, there is 1 leaf node. Then we should output 0 1 in a line.

Sample Input:

2 1
01 1 02

Sample Output:

0 1

Python实现：

def dfs(node, depth):
    is_visited[node] = True
    global max_depth
    max_depth = max(max_depth, depth)
    if node not in tree:
        num_leaf_node[depth] += 1
        return
    for child in tree[node]:
        if child not in is_visited:
            dfs(child, depth + 1)  # 递归


n, m = list(map(int, input().split()))  # n:树中节点数,m:非叶节点数
tree = {}  # 用字典表示树
max_depth = 0  # 树的深度
num_leaf_node = [0] * (n + 1)  # 同一深度的叶子节点数
is_visited = {}  # 节点是否已访问
for i in range(m):  # 初始化树
    node_id, children, *child_id = input().split()  # 如果化成int处理，测试点4报非零返回
    tree[node_id] = child_id
dfs('01', 0)
print(" ".join(str(i) for i in num_leaf_node[0:max_depth + 1]))

提交结果：

提交时间	状态	分数	题目	编译器	耗时	用户
2019/12/4 22:11:44	答案正确	30	1004	Python (python 3)	22 ms	哆啦一泓

测试点	结果	耗时	内存
0	答案正确	22 ms	2896 KB
1	答案正确	16 ms	2984 KB
2	答案正确	17 ms	2888 KB
3	答案正确	17 ms	2968 KB
4	答案正确	20 ms	2944 KB
5	答案正确	17 ms	2888 KB