[leet] bst

Author: hyeonbinHur

허현빈/11주차/Symmetric Tree.js

@@ -0,0 +1,21 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {boolean}
+ */
+var isSymmetric = function(root) {
+    const isMirror = (left, right) =>{
+        if(!left && !right) return true
+        if(!left || !right) return false
+        if(left.val !== right.val) return false
+        return isMirror(left.left, right.right) && isMirror(left.right, right.left)
+    }
+    return isMirror(root.left, root.right)
+};