将二叉树转成双向链表。

将有序数组转换成二叉搜索树

108. Convert Sorted Array to Binary Search Tree

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

IO复用是在阻塞IO基础上，通过某种机制同时对多个文件描述符进行监视的一种方式。

linux权限是linux中很重要的一部分。

当从容器中删除元素或者向容器中添加元素时，会出现迭代器失效问题。

Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.

Single Number系列

Given a binary tree, return the postorder traversal of its nodes’ values.

智能指针有三类: shared_ptr, unique_ptr, weak_ptr.
其中shared_ptr可以和其他shared_ptr共享内存,指向同一块内存区域,引用计数用于记录指向该内存的shared_ptr个数.

类型转换