add issymmetric in js and py

Author: akgmage

Trees/Binary Trees/is_symmetric.js

@@ -0,0 +1,50 @@
+/*
+  Write a function that takes in a Binary Tree and returns if that tree is symmetrical. A tree is symmetrical 
+  if the left and right subtrees are mirror images of each other.
+*/
+class BinaryTree {
+  constructor(value, left = null, right = null) {
+    this.value = value;
+    this.left = left;
+    this.right = right;
+  }
+}
+
+function isSymmetricalTreeIterative(tree) {
+  const stackLeft = (tree && [tree.left]) || []; // Initialize stackLeft with the left child of the root node
+  const stackRight = (tree && [tree.right]) || []; // Initialize stackRight with the right child of the root node
+
+  // Perform mirror traversal of the left and right subtrees
+  while (stackLeft.length > 0) {
+    const left = stackLeft.pop() || null; // Pop the top node from stackLeft
+    const right = stackRight.pop() || null; // Pop the top node from stackRight
+
+    if (!left && !right) {
+      continue; // Both left and right subtrees are symmetric, continue to the next iteration
+    }
+
+    if (!left || !right || left.value !== right.value) {
+      return false; // Asymmetry detected, tree is not symmetric
+    }
+
+    // Push the children of left and right onto the respective stacks in reverse order
+    if (left) {
+      stackLeft.push(left.left, left.right);
+    }
+    if (right) {
+      stackRight.push(right.right, right.left);
+    }
+  }
+
+  return true; // Tree is symmetric
+}
+
+// Example usage:
+// Construct a symmetric tree
+const symmetricTree = new BinaryTree(
+  1,
+  new BinaryTree(2, new BinaryTree(3), new BinaryTree(4)),
+  new BinaryTree(2, new BinaryTree(4), new BinaryTree(3))
+);
+
+console.log(isSymmetricalTreeIterative(symmetricTree)); // Output: true

Trees/Binary Trees/is_symmetric.py

@@ -0,0 +1,36 @@
+'''
+  Write a function that takes in a Binary Tree and returns if that tree is symmetrical. A tree is symmetrical 
+  if the left and right subtrees are mirror images of each other.
+'''
+class BinaryTree:
+    def __init__(self, value, left=None, right=None):
+        self.value = value
+        self.left = left
+        self.right = right
+
+def is_symmetrical_tree_iterative(tree):
+    stack_left = [tree.left] if tree else []  # Initialize stackLeft with the left child of the root node
+    stack_right = [tree.right] if tree else []  # Initialize stackRight with the right child of the root node
+
+    # Perform mirror traversal of the left and right subtrees
+    while stack_left:
+        left = stack_left.pop() if stack_left else None
+        right = stack_right.pop() if stack_right else None
+
+        if not left and not right:
+            continue  # Both left and right subtrees are symmetric, continue to the next iteration
+
+        if not left or not right or left.value != right.value:
+            return False  # Asymmetry detected, tree is not symmetric
+
+        # Push the children of left and right onto the respective stacks in reverse order
+        stack_left.extend([left.left, left.right] if left else [])
+        stack_right.extend([right.right, right.left] if right else [])
+
+    return True  # Tree is symmetric
+
+# Example usage:
+# Construct a symmetric tree
+symmetric_tree = BinaryTree(1, BinaryTree(2, BinaryTree(3), BinaryTree(4)), BinaryTree(2, BinaryTree(4), BinaryTree(3)))
+
+print(is_symmetrical_tree_iterative(symmetric_tree))  # Output: True