摘要：Hadoop HDFS源码分析 关于数据块的类1.BlocksMap官方代码中的注释为：/** * This class maintains the map from a block to its metadata. * block's metadata currently includes blo... 阅读全文

摘要：读取命名空间镜像和编辑日志数据1.读取命名空间镜像类FSImage是 命名空间镜像的java实现，在源码中，英文注释为，/** * FSImage handles checkpointing and logging of the namespace edits. * */FSImage.loadFS... 阅读全文

摘要：Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2]have the following unique perm... 阅读全文

摘要：Write a program to solve a Sudoku puzzle by filling the empty cells.Empty cells are indicated by the character'.'.You may assume that there will be on... 阅读全文