编写一程序构造二叉树b,并输出二叉树b的叶子结点个数以及叶子结点对应的字符

首先，我们需要定义一个二叉树节点结构，包括数据和指向左右子节点的指针。然后我们可以创建一个函数来构建二叉树，并遍历这个树来找出所有叶子节点及其对应的字符。

# 定义二叉树节点
class TreeNode:
    def __init__(self, data):
        self.data = data
        self.left = None
        self.right = None

def build_binary_tree(b, root_data):
    # 根据给定的数据列表构建二叉树
    if b:
        mid = len(b) // 2
        root = TreeNode(b[mid])
        root.left = build_binary_tree(b[:mid], "") if mid > 0 else None
        root.right = build_binary_tree(b[mid + 1:], "") if mid < len(b) - 1 else None
    return root

def count_leaf_nodes_and_chars(root):
    leaf_count = 0
    leaf_nodes = []

    def is_leaf(node):
        return node.left is None and node.right is None

    def traverse(node, char=None):
        nonlocal leaf_count
        if node is not None:
            char = node.data if is_leaf(node) else char
            if is_leaf(node):
                leaf_count += 1
                leaf_nodes.append(char)
            traverse(node.left, char)
            traverse(node.right, char)

    traverse(root)
    return leaf_count, leaf_nodes

# 示例：输入一个字符串列表构建二叉树
b = ["A", "B", "D", "E", "F", "G"]
root = build_binary_tree(b, "")

# 计算并输出结果
leaf_count, leaf_chars = count_leaf_nodes_and_chars(root)
print(f"叶子节点个数: {leaf_count}")
print(f"叶子节点对应的字符: {leaf_chars}")