来源 http://www.open-mpi.org/ 网络连接 SSH连接，保证各台机器之间可以无密码登陆，此处不展开 hosts文件如下 安装第一步 ./configure --prefix=/home/hadoop/openmpi_install 注：prefix后面是安装路径 可能会出现co Read More
挂载硬盘 sudo mount -t ext4 /dev/sdb1 /media/hadoop 自动挂载相关 sudo blkid sudo fdisk -l vim /etc/fstab cat /etc/mtab 虚拟机安装VM tools 初始目录： centOS：/run/media/use Read More
题目来源https://leetcode.com/problems/search-a-2d-matrix/Write an efficient algorithm that searches for a value in anmxnmatrix. This matrix has the follow... Read More
map将RDD中的每个数据项，一对一的映射关系，RDD数目不变，分区数也不变例子：数据集：map操作：flatMap和map一样，但是会拆分每一个map之后的list，可以理解为一对多（注：会把字符串当作数组然后拆分）例子：distinct对RDD的数据项进行去重操作例子：coalescedef c... Read More
firstdef first(): Tfirst返回RDD中的第一个元素，不排序。例子：countdef count(): Longcount返回RDD中的元素数量例子：reducedef reduce(f: (T, T) ⇒ T): T根据映射函数f，对RDD中的元素进行二元计算，返回计算结果（可... Read More
saveAsTextFilesaveAsTextFile(path,compressionCodecClass=None)aveAsTextFile用于将RDD以文本文件的格式存储到文件系统中， 将每一个元素以string格式存储（结合python的loads和dumps可以很好应用）Paramet... Read More
题目来源https://leetcode.com/problems/excel-sheet-column-title/Given a positive integer, return its corresponding column title as appear in an Excel sheet... Read More
题目来源https://leetcode.com/problems/anagrams/Given an array of strings, group anagrams together.For example, given:["eat", "tea", "tan", "ate", "nat", "... Read More
题目来源https://leetcode.com/problems/minimum-path-sum/Given amxngrid filled with non-negative numbers, find a path from top left to bottom right whichmin... Read More
题目来源https://leetcode.com/problems/unique-paths-ii/Follow up for "Unique Paths":Now consider if some obstacles are added to the grids. How many unique ... Read More