binary tree

Binary Tree Inorder Traversal

Binary Tree Inorder Traversal asks you to visit left subtree, node, then right subtree without losing position while mov…

Unique Binary Search Trees II

Generate all structurally unique BSTs with values 1 to n using backtracking and recursive tree construction techniques.

Unique Binary Search Trees

Given n nodes, calculate the number of unique binary search trees (BSTs) that can be formed with values from 1 to n.

Validate Binary Search Tree

Validate Binary Search Tree problem checks if a binary tree satisfies BST properties using tree traversal and state trac…

Recover Binary Search Tree

Recover a BST where two nodes are swapped by mistake using in-order traversal and careful state tracking to restore corr…

Same Tree

Check whether two binary trees are identical by comparing structure and node values using DFS or BFS traversal strategie…

Symmetric Tree

Determine if a binary tree is symmetric by comparing left and right subtrees using DFS or BFS traversal techniques effic…

Binary Tree Level Order Traversal

Perform a level order traversal on a binary tree using BFS to return node values level by level.

Binary Tree Zigzag Level Order Traversal

Traverse a binary tree in zigzag level order, alternating directions at each depth using BFS and state tracking techniqu…

Maximum Depth of Binary Tree

Find the maximum depth of a binary tree using traversal techniques to track the longest path from root to leaf.

Construct Binary Tree from Preorder and Inorder Traversal

Construct a binary tree using preorder and inorder traversal arrays, leveraging array scanning and hash table lookups.

Construct Binary Tree from Inorder and Postorder Traversal

Reconstruct a binary tree from given inorder and postorder arrays using array scanning and hash lookup to optimize recur…

Binary Tree Level Order Traversal II

Return a bottom-up level order traversal of a binary tree, processing nodes left to right while tracking each level accu…

Convert Sorted Array to Binary Search Tree

Pick the middle element as root at each step so the sorted array becomes a height-balanced BST with valid ordering.

Convert Sorted List to Binary Search Tree

Convert a sorted singly linked list into a height-balanced BST using pointer manipulation and divide-and-conquer recursi…

Balanced Binary Tree

Determine if a binary tree is height-balanced using tree traversal and state tracking techniques.

Minimum Depth of Binary Tree

Find the minimum depth of a binary tree, which is the shortest path from the root node to the nearest leaf node.

Path Sum

Determine if a binary tree has a root-to-leaf path where the sum of node values equals a given target sum, using DFS or …

Path Sum II

Find all root-to-leaf paths in a binary tree where the sum of node values equals a given target using DFS backtracking.

Flatten Binary Tree to Linked List

Flatten a binary tree into a right-skewed linked list by manipulating pointers following a pre-order traversal, handling…

Populating Next Right Pointers in Each Node

Connect each node across every level by reusing established next links to traverse a perfect binary tree without extra q…

Populating Next Right Pointers in Each Node II

Populate each next pointer in a binary tree to its immediate right node, handling nulls and uneven levels efficiently us…

Binary Tree Maximum Path Sum

Calculate the maximum sum of any path in a binary tree by exploring all node sequences using DFS and dynamic programming…

Sum Root to Leaf Numbers

Calculate the sum of all root-to-leaf numbers in a binary tree where each path represents a number.