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：
Write a function to generate the generalized abbreviations of a word. Note: The order of the output does not matter. Example: Input: "word" Output: [" 阅读全文
摘要：
Given a string that contains only digits 0-9 and a target value, return all possibilities to add binary operators (not unary) +, -, or * between the d 阅读全文