> For the complete documentation index, see [llms.txt](https://syjohnson11.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://syjohnson11.gitbook.io/leetcode/0.-introduction/02_zhong_dian_ti_ji_lu.md).

# 0.2 重点题纪录

* 3.longest substring without repeating character(hashmap+two pointer)
* 4.Find median of two sorted array
* 5.longest palindromic substring
* 23.Merge K sorted List using merge sort(instead of PQ)
* 31.Next Permutation
* 60.Permutation sequence
* 96.Unique BST I II
* 98.Validate BST
* 109.Convert sorted list to BST
* 124.binary tree maximum path sum
* 146.LRU Cache(Linked List)
* 164.Maximum gap(bucket sort) bug free难，面试写Radix sort
* 215.Kth largest element in array
* 1. Search in a 2D matrix II(取右上角，每次舍弃一列或者一行)
* 267.Permutation II
* 270.Closest Binary Search Tree Value
* 271.Decode and Encode String(length + "#" + string, 不要用s.split("#")), FOLLOW UP: 不记录length
* 295.Find median from data stream(minHeap and maxHeap)
* 324.Wiggle sort II(quickselect & virtual indexing)强记
* 377.Combination Sum IV(top-down and bottom-up)
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