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摘要： 题目：Given two integersnandk, return all possible combinations ofknumbers out of 1 ...n.For example,Ifn= 4 andk= 2, a solution is:[ [2,4], [3,4], [2,... 阅读全文

摘要： 题目：Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2]have the following unique p... 阅读全文

摘要： 题目：Given a collection of numbers, return all possible permutations.For example,[1,2,3]have the following permutations:[1,2,3],[1,3,2],[2,1,3],[2,3,1],... 阅读全文