摘要：
Given an array of integers sorted in ascending order, find the starting and ending position of a given target value. Your algorithm's runtime complexi 阅读全文
摘要：
Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array whic 阅读全文
摘要：
Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. 阅读全文