摘要：
Given a list of numbers with duplicate number in it. Find all unique permutations. Example For numbers [1,2,2] the unique permutations are: [ [1,2,2], 阅读全文
摘要：
Given a list of numbers, return all possible permutations. Notice You can assume that there is no duplicate numbers in the list. Example For nums = [1 阅读全文
摘要：
Given a list of numbers that may has duplicate numbers, return all possible subsets Notice Each element in a subset must be in non-descendingorder. Th 阅读全文
摘要：
Given a set of distinct integers, return all possible subsets. Notice Elements in a subset must be in non-descending order. The solution set must not 阅读全文