摘要：Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjac 阅读全文

摘要：A mapping of digit to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters. Example: For static final, 阅读全文

摘要：Given a string S, we can transform every letter individually to be lowercase or uppercase to create another string. Return a list of all possible stri 阅读全文

摘要：Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be 阅读全文

摘要：Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numb 阅读全文

摘要：Given a set of candidate numbers (candidates) (without duplicates) and a target number (target), find all unique combinations in candidates where the 阅读全文

摘要：我写的 [1,4] is the same as [4,1] in the combination sense because in combination ,[1,4] is the same as [4,1], so we want to sort the array first and 1,1 阅读全文

摘要：Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: ( 阅读全文

摘要：solution 2 : (1) used hashset to record used elements and pass the hashset for the next level on the current level, we need to do the backtrack recove 阅读全文

摘要：Given a collection of integers that might contain duplicates, nums, return all possible subsets (the power set). Note: The solution set must not conta 阅读全文

摘要：(面经 Find the number of subsets which the sum of min value in subset and max value in subset smaller or equal to the given target) https://www.journald 阅读全文