摘要： Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1：Input: haystack = "hello", needle = 阅读全文

摘要： Given an array nums and a value val, remove all instances of that value in-place and return the new length. Do not allocate extra space for another ar 阅读全文

摘要： Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length. Do not allocate extra spa 阅读全文