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Add Binary Tree Symmetry
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kotlin/Trees/BinaryTreeSymmetry.kt

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import ds.TreeNode
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/*
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Definition of TreeNode:
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data class TreeNode(
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var value: 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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fun binaryTreeSymmetry(root: TreeNode?): Boolean {
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if (root == null) {
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return true
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}
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return compareTrees(root.left, root.right)
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}
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fun compareTrees(node1: TreeNode?, node2: TreeNode?): Boolean {
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// Base case: if both nodes are null, they're symmetric.
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if (node1 == null && node2 == null) {
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return true
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}
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// If one node is null and the other isn't, they aren't symmetric.
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if (node1 == null || node2 == null) {
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return false
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}
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// If the values of the current nodes don't match, trees aren't symmetric.
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if (node1.value != node2.value) {
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return false
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}
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// Compare the 'node1's left subtree with 'node2's right subtree. If these
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// aren't symmetric, the whole tree is not symmetric.
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if (!compareTrees(node1.left, node2.right)) {
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return false
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}
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// Compare the 'node1's right subtree with 'node2's left subtree.
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return compareTrees(node1.right, node2.left)
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}

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