摘要：
Given a sorted array of integers, find the starting and ending position of a given target value.Your algorithm's runtime complexity must be in the ord... 阅读全文
摘要：
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], [2,3],... 阅读全文