Tree Includes Approach

In this lesson, Alvin explores the strategy to solving the following interview problem:

Write a function, tree_includes, that takes in the root of a binary tree and a target value. The function should return a boolean indicating whether or not the value is contained in the tree.

a = Node("a")
b = Node("b")
c = Node("c")
d = Node("d")
e = Node("e")
f = Node("f")
a.left = b
a.right = c
b.left = d
b.right = e
c.right = f

#      a
#    /   \
#   b     c
#  / \     \
# d   e     f

tree_includes(a, "e") # -> True

a = Node("a")
b = Node("b")
c = Node("c")
d = Node("d")
e = Node("e")
f = Node("f")
a.left = b
a.right = c
b.left = d
b.right = e
c.right = f

#      a
#    /   \
#   b     c
#  / \     \
# d   e     f

tree_includes(a, "a") # -> True

a = Node("a")
b = Node("b")
c = Node("c")
d = Node("d")
e = Node("e")
f = Node("f")
a.left = b
a.right = c
b.left = d
b.right = e
c.right = f

#      a
#    /   \
#   b     c
#  / \     \
# d   e     f

tree_includes(a, "n") # -> False

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