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

摘要： 问题：如何随机从n个对象中选择一个对象，这n个对象是按序排列的，但是在此之前你是不知道n的值的。 思路：如果我们能够知道n的值，那么问题就简单了，只需要randInt(n)得到确切的位置，然后选择出该位置的值即可，实现概率为1/n的抽样。 但现在我们并不知道n的值，这个问题便抽象为蓄水池抽样，即从一 阅读全文

摘要： 题目描述： Given a non-negative integer n, count all numbers with unique digits, x, where 0 ≤ x < 10n. Example:Given n = 2, return 91. (The answer should b 阅读全文

摘要： 题目描述： Given a non-empty array of integers, return the k most frequent elements. For example,Given [1,1,1,2,2,3] and k = 2, return [1,2]. Note: You may 阅读全文

摘要： 题目描述： We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you gues 阅读全文

摘要： 题目描述： Given an integer (signed 32 bits), write a function to check whether it is a power of 4. Example:Given num = 16, return true. Given num = 5, ret 阅读全文

摘要： 题目描述： 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:Gi 阅读全文

摘要： 题目描述： Given a linked list, determine if it has a cycle in it. 解题思路： 快的指针和慢的指针 代码如下： 阅读全文

摘要： 题目描述： Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at most one trans 阅读全文

摘要： 题目描述： Given two arrays, write a function to compute their intersection. Example:Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2, 2]. Note: Each 阅读全文