Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for ‘?’ and ‘*’ where: ‘?’ Matches any single character.’*’ Matches any sequence of characters (including the empty sequence).The matching should cover the entire input string.
Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to target.
Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. You may return the combinations in any order.
Write a program to solve a Sudoku puzzle by filling the empty cells.
Given the head of a singly linked list, reverse the list, and return the reversed list.