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摘要： Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library functio 阅读全文

摘要： Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted i 阅读全文

摘要： Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in or 阅读全文

摘要： Given a binary search tree, write a function kthSmallest to find the kth smallest element in it. Note: You may assume k is always valid, 1 ≤ k ≤ BST's 阅读全文

摘要： Given a n x n matrix where each of the rows and columns are sorted in ascending order, find the kth smallest element in the matrix. Note that it is th 阅读全文

摘要： Given a string s and a string t, check if s is subsequence of t. You may assume that there is only lower case English letters in both s and t. t is po 阅读全文

摘要： Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: 阅读全文

摘要： Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the rans 阅读全文

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

摘要： Write a function that takes a string as input and reverse only the vowels of a string. Example 1: Given s = "hello", return "holle". Example 2: Given 阅读全文