摘要：
Two elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Note:A solution using O(n) space is ... 阅读全文
摘要：
Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters fo... 阅读全文
摘要：
Given an unsorted integer array, find the first missing positive integer.For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2.Your algorithm sho... 阅读全文
摘要：
The set [1,2,3,…,n] contains a total of n! unique permutations.By listing and labeling all of the permutations in order,We get the following sequence ... 阅读全文