tree_candidates = dict() Node_num, root_val = map(int, input().split()) for _ in range(Node_num): root, left, right = map(int, input().split()) tree_candidates[root]=[left, right] #前序遍历,tree_candidates也可以不作为入口参数传入,直接作为全局变量来读取 def pre_traversal(root, tree_candidates): print(root, e...