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31 lines
579 B
Ruby
31 lines
579 B
Ruby
# Checks if a binary tree is balanced in O(n) time and O(height) space,
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# see examples in test/btree_test.rb
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class BTree
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Node = Struct.new(:left, :right)
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def initialize(node)
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@height = height(node)
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end
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def balanced?
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@height != -1
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end
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private
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def height(node)
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return 0 if node.nil?
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left_height = height(node.left)
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return -1 if left_height == -1
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right_height = height(node.right)
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return -1 if right_height == -1
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diff = left_height - right_height
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return -1 if diff.abs > 1
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[left_height, right_height].max + 1
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end
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end
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