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)