Pretty Sure

LeetCode - Mini Parser

Question Definition

Given a nested list of integers represented as a string, implement a parser to deserialize it.

Each element is either an integer, or a list – whose elements may also be integers or other lists.

LeetCode - Evaluate Reverse Polish Notation

Question Definition

Evaluate the value of an arithmetic expression in Reverse Polish Notation.

Valid operators are +, -, *, /. Each operand may be an integer or another expression.

LeetCode - 132 Pattern

Question Definition

Given a sequence of n integers a1, a2, …, an, a 132 pattern is a subsequence ai, aj, ak such that i < j < k and ai < ak < aj. Design an algorithm that takes a list of n numbers as input and checks whether there is a 132 pattern in the list.

LeetCode - Word Ladder

Question Definition

Given two words (beginWord and endWord), and a dictionary’s word list, find the length of shortest transformation sequence from beginWord to endWord, such that:

1. Only one letter can be changed at a time.

2. Each transformed word must exist in the word list. Note that beginWord is not a transformed word.

LeetCode - Peeking Iterator

Question Definition

Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that support the peek() operation – it essentially peek() at the element that will be returned by the next call to next().