摘要：
题目介绍： Given a string which contains only lowercase letters, remove duplicate letters so that every letter appear once and only once. You must make sur 阅读全文
摘要：
问题描述： Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree is symmetric: But t 阅读全文
摘要：
问题描述： You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the qua 阅读全文
摘要：
问题描述： Given a non-negative number represented as an array of digits, plus one to the number. The digits are stored such that the most significant digi 阅读全文
摘要：
问题描述： Reverse digits of an integer. Example1: x = 123, return 321Example2: x = -123, return -321 分析：将一个整数逆序输出，需要判断是否越界。Integer.MAX_VALUE，Integer.MIN_V 阅读全文
摘要：
算法描述： Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length. Do not allocate extra sp 阅读全文
摘要：
问题描述： Given an array and a value, remove all instances of that value in place and return the new length. The order of elements can be changed. It does 阅读全文
摘要：
问题描述： Write a program to find the n-th ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 1, 2, 3, 阅读全文
