54 lines
1.1 KiB
Python
54 lines
1.1 KiB
Python
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class TreeNode:
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def __init__(self, val):
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self.val = val
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self.left = None
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self.right = None
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'''
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A tree is balanced if the height of the left and right subtrees do not differ by more than 1
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two approaches given by: https://www.youtube.com/watch?v=LU4fGD-fgJQ
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this is approach #1 (inefficient because all nodes will call the height() function)
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'''
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def isTreeBalanced(root):
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if not root:
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return True
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if root:
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leftHeight = height(root.left)
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rightHeight = height(root.right)
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currNodeBalanced = abs(leftHeight-rightHeight) <= 1
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lesRes = isTreeBalanced(root.left)
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rightRes = isTreeBalanced(root.right)
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return currNodeBalanced and lesRes and rightRes
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def height(root):
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if not root:
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return 0
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else:
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return 1+max( height(root.left), height(root.right) )
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root = TreeNode(1)
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root.left = TreeNode(2)
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root.right = TreeNode(3)
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root.right.right = TreeNode(20)
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# root.right.right.right = TreeNode(20)
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# print(height(root.right))
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print( isTreeBalanced(root) )
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