摘要：
Given a collection of distinct numbers, return all possible permutations. For example,[1,2,3] have the following permutations: [ [1,2,3], [1,3,2], [2, 阅读全文
摘要：
Given a collection of integers that might contain duplicates, nums, return all possible subsets. Note: The solution set must not contain duplicate sub 阅读全文