30 lines
665 B
Kotlin
30 lines
665 B
Kotlin
/**
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* Example:
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* var ti = TreeNode(5)
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* var v = ti.`val`
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* Definition for a binary tree node.
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* class TreeNode(var `val`: Int) {
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* var left: TreeNode? = null
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* var right: TreeNode? = null
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* }
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*/
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class Solution {
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fun tree2str(root: TreeNode?): String {
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if (root == null) {
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return ""
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}
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val value = root.`val`.toString()
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val left = "(${tree2str(root.left)})"
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val right = "(${tree2str(root.right)})"
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if (left == "()" && right == "()") {
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return value
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} else if (right == "()") {
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return "$value$left"
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}
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return "$value$left$right"
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}
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}
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