Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path betwe ...

Given the root of a binary tree with N nodes, each node in the tree has node.val coins, and there are N coins total. In one move, we may choose two ad ...

Given an encoded string, return it’s decoded string. The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is b ...

Sometimes people repeat letters to represent extra feeling, such as “hello” -> “heeellooo”, “hi” -> “hiiii”. In these strings like “heeellooo”, ...

Given a nested list of integers, implement an iterator to flatten it. Each element is either an integer, or a list – whose elements may also be intege ...

Write an iterator that iterates through a run-length encoded sequence. The iterator is initialized by RLEIterator(int[] A), where A is a run-length en ...

Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that support the peek() operation – it es ...

Implement an iterator to flatten a 2d vector. ExampleNo.1Input:[[1,2],[3],[4,5,6]] Output:[1,2,3,4,5,6] No.2Input:[[7,9],[5]] Output:[7,9,5] Code12345 ...

TinyURL is a URL shortening service where you enter a URL such as https://leetcode.com/problems/design-tinyurl and it returns a short URL such as http ...

A complete binary tree is a binary tree in which every level, except possibly the last, is completely filled, and all nodes are as far left as possibl ...