27 lines
455 B
Go
27 lines
455 B
Go
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package main
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func bstToGst(root *TreeNode) *TreeNode {
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var rec func(*TreeNode, int) int
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rec = func(node *TreeNode, toAdd int) int {
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if node == nil {
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return toAdd
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}
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// recurse to right
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toAdd = rec(node.Right, toAdd)
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// add to the current value
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originalValue := node.Val
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node.Val += toAdd
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// pass new sum to the left
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toAdd = rec(node.Left, toAdd+originalValue)
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// return new sum
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return toAdd
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}
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rec(root, 0)
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return root
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}
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