Just DO IT by luckygxf

摘要： Path Sum IIGiven a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.For example:Given the below binary tr... 阅读全文

摘要： java synchronized主要用于控制线程同步，中间有很多小的细节，知识，这里我简单的整理一下，做个记录。主要用于方法和代码块的控制先说说方法控制模拟银行存款和取款，创建一个Account类，两个属性，一个name和accout。先存1w进去，在用一100个线程取钱1k和存1k。等待所有线程... 阅读全文

摘要： Sum Root to Leaf NumbersGiven a binary tree containing digits from0-9only, each root-to-leaf path could represent a number.An example is the root-to-l... 阅读全文

摘要： Letter Combinations of a Phone NumberGiven a digit string, return all possible letter combinations that the number could represent.A mapping of digit ... 阅读全文

摘要： 多个线程访问同一个变量时，可能会出现问题。这里我用两个线程同时访问一个int count变量，让他们同时+1。同时让线程睡眠1秒，每个线程执行10次，最后应该输出20才对，因为count++并不是原子操作，这里需要做并发处理，如用syn...什么关键词，当然还有别的方法。后面在说这里为了是两个线程访... 阅读全文

摘要： Spiral Matrix IIGiven an integern, generate a square matrix filled with elements from 1 ton2in spiral order.For example,Givenn=3,You should return the... 阅读全文

摘要： Spiral MatrixGiven a matrix ofmxnelements (mrows,ncolumns), return all elements of the matrix in spiral order.For example,Given the following matrix:[... 阅读全文

摘要： Search in Rotated Sorted Array IIFollow up for "Search in Rotated Sorted Array":What ifduplicatesare allowed?Would this affect the run-time complexity... 阅读全文

摘要： Search in Rotated Sorted ArraySuppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e.,0 1 2 4 5 6 7might become4 5 6 7 0 1 2).... 阅读全文

摘要： Best Time to Buy and Sell Stock IISay you have an array for which theithelement is the price of a given stock on dayi.Design an algorithm to find the ... 阅读全文