1 min readAug 7, 2020
There is a mistake in Class leaf ,the constructor must be Leaf(this.value) instead of Root(this.value)
Sign up to discover human stories that deepen your understanding of the world.
Free
Distraction-free reading. No ads.
Organize your knowledge with lists and highlights.
Tell your story. Find your audience.
Membership
Read member-only stories
Support writers you read most
Earn money for your writing
Listen to audio narrations
Read offline with the Medium app
