Create diameterOfBinaryTree.js

Author: RinkiJhunjhunwala

Trees/diameterOfBinaryTree.js

@@ -0,0 +1,30 @@
+/**
+ * Calculates the diameter of a binary tree.
+ * The diameter is the length of the longest path between any two nodes.
+ * @param {TreeNode} root The root node of the tree.
+ * @returns {number} The diameter of the tree.
+ */
+export function diameterOfBinaryTree(root) {
+  let diameter = 0;
+
+  // This helper function returns the height of a subtree,
+  // but it calculates and updates the diameter as a side effect.
+  function height(node) {
+    if (node === null) {
+      return 0;
+    }
+
+    const leftHeight = height(node.left);
+    const rightHeight = height(node.right);
+
+    // The diameter at this node is the sum of the heights of its subtrees.
+    // We update the global maximum diameter if this path is longer.
+    diameter = Math.max(diameter, leftHeight + rightHeight);
+
+    // The height of the tree at this node is 1 + the max height of its subtrees.
+    return 1 + Math.max(leftHeight, rightHeight);
+  }
+
+  height(root);
+  return diameter;
+}