algorithms-python/algorithms/tree/is_balanced.py at master · ivan1911/algorithms-python · GitHub

37 lines (30 loc) · 833 Bytes

def is_balanced(root):

return __is_balanced_recursive(root)

def __is_balanced_recursive(root):

"""

O(N) solution

"""

return -1 != __get_depth(root)

def __get_depth(root):

"""

return 0 if unbalanced else depth + 1

"""

if root is None:

return 0

left = __get_depth(root.left)

right = __get_depth(root.right)

if abs(left-right) > 1 or -1 in [left, right]:

return -1

return 1 + max(left, right)

# def is_balanced(root):

# """

# O(N^2) solution

# """

# left = max_height(root.left)

# right = max_height(root.right)

# return abs(left-right) <= 1 and is_balanced(root.left) and

# is_balanced(root.right)

# def max_height(root):

# if root is None:

# return 0

# return max(max_height(root.left), max_height(root.right)) + 1

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