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25 lines
619 B
Ruby
25 lines
619 B
Ruby
# Given a binary tree and a sum, determine if the tree has a root-to-leaf path
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# such that adding up all the values along the path equals the given sum.
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# Definition for a binary tree node.
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# class TreeNode
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# attr_accessor :val, :left, :right
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# def initialize(val)
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# @val = val
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# @left, @right = nil, nil
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# end
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# end
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# @param {TreeNode} root
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# @param {Integer} sum
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# @return {Boolean}
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def path_sum?(root, sum)
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return false unless root
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if root.left || root.right
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return path_sum?(root.left, sum - root.val) || path_sum?(root.right, sum - root.val)
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end
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sum - root.val == 0
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end
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