Posted on Fri 07 February 2025 in Leetcode • Tagged with recursion, serialization
Question Link : https://leetcode.com/problems/mini-parser/
Difficulty: Medium
Premium: False
Given a string s represents the serialization of a nested list, implement a parser to deserialize it and return the deserialized NestedInteger. Each element is either an integer or a list whose elements may also be integers or …
Posted on Thu 06 February 2025 in Leetcode • Tagged with binary-tree, recursion
Question Link : https://leetcode.com/problems/balanced-binary-tree/
Difficulty: Easy
Premium: False
Given a binary tree, determine if it is height-balanced. Example 1:
Input: root = [3,9,20,null,null,15,7] Output: true
Example 2:
Input: root = [1,2,2,3,3,null,null,4,4] Output: false
Example …
Posted on Thu 16 January 2025 in Leetcode • Tagged with string, recursion
Question Link : https://leetcode.com/problems/integer-to-english-words/
Difficulty: Hard
Premium: False
Convert a non-negative integer num to its English words representation. Example 1:
Input: num = 123 Output: "One Hundred Twenty Three"
Example 2:
Input: num = 12345 Output: "Twelve Thousand Three Hundred Forty Five"
Example 3:
Input: num = 1234567 Output …
Posted on Mon 06 January 2025 in Leetcode • Tagged with binary-tree-traversal-level-order, bfs-layered, recursion
Question Link : https://leetcode.com/problems/binary-tree-level-order-traversal/
Difficulty: Medium
Premium: False
Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level). Example 1:
Input: root = [3,9,20,null,null,15,7] Output: [[3 …
Posted on Tue 05 November 2024 in Leetcode • Tagged with trie-prefix-tree, dfs, recursion
Question Link : https://leetcode.com/problems/design-add-and-search-words-data-structure/
Difficulty: Medium
Premium: False
Design a data structure that supports adding new words and finding if a string matches any previously added string. Implement the WordDictionary class:
WordDictionary() Initializes the object. void addWord(word) Adds word to the data structure, it can …
Posted on Wed 25 September 2024 in Leetcode • Tagged with bst, recursion
Question Link : https://leetcode.com/problems/validate-binary-search-tree/
Difficulty: Medium
Premium: False
Given the root of a binary tree, determine if it is a valid binary search tree (BST). A valid BST is defined as follows:
The left subtree of a node contains only nodes with keys less than the …
Posted on Mon 13 March 2023 in Leetcode • Tagged with recursion, binary-tree
Question Link : https://leetcode.com/problems/sum-root-to-leaf-numbers/
Difficulty: Medium
Premium: False
You are given the root of a binary tree containing digits from 0 to 9 only. Each root-to-leaf path in the tree represents a number.
For example, the root-to-leaf path 1 -> 2 -> 3 represents the number 123.
Return …
Posted on Mon 09 January 2023 in Leetcode • Tagged with binary-tree-traversal, recursion
Question Link : https://leetcode.com/problems/same-tree/
Difficulty: Easy
Premium: False
Given the roots of two binary trees p and q, write a function to check if they are the same or not. Two binary trees are considered the same if they are structurally identical, and the nodes have …
Posted on Sat 10 December 2022 in Leetcode • Tagged with recursion, binary-tree
Question Link : https://leetcode.com/problems/binary-tree-maximum-path-sum/
Difficulty: Hard
Premium: False
A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequence at most once. Note that …
Posted on Tue 06 December 2022 in Leetcode • Tagged with bst, recursion
Question Link : https://leetcode.com/problems/range-sum-of-bst/
Difficulty: Easy
Premium: False
Given the root node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high]. Example 1:
Input: root = [10,5 …