刷题记录

4/12/18 ~ 4/14/18

List

• 380        Insert Delete GetRandom O(1)
• 381        Insert Delete GetRandom O(1) - Duplicates allowed
• 146        LRU Cache
• 460        LFU Cache
• 432        All O`one Data Structure
  

Stack

• 155        Min Stack
• 225        Implement Stack using Queues
• 232        Implement Queue using Stacks
  

Iterator

• 251        Flatten 2D Vector
• 281        Zigzag Iterator
• 284        Peeking Iterator
• 341        Flatten Nested List Iterator
• 604        Design Compressed String Iterator
• 173        Binary Search Tree Iterator
  

Queue & Set

• 353        Design Snake Game
• 379        Design Phone Directory
• 635        Design Log Storage System
  

HashTable

• 631        Design Excel Sum Formula
• 359        Logger Rate Limiter
• 362        Design Hit Counter
• 535        Encode and Decode TinyURL
  

Trie

• 208        Implement Trie (Prefix Tree)
• 211        Add and Search Word - Data structure design
• 677        Map Sum Pairs
• 642        Design Search Autocomplete System
  

4/15/18 ~ 4/16/18

Tree Traversal

• 94        Binary Tree Inorder Traversal
• 144        Binary Tree Preorder Traversal
• 145        Binary Tree Postorder Traversal
• 173        Binary Search Tree Iterator
• 98        Validate Binary Search Tree
• 99        Recover Binary Search Tree
• 285        Inorder Successor in BST
• 606        Construct String from Binary Tree
• 105        Construct Binary Tree from Preorder and Inorder Traversal
• 106        Construct Binary Tree from Inorder and Postorder Traversal
• 255        Verify Preorder Sequence in Binary Search Tree
• 501        Find Mode in Binary Search Tree
• 653        Two Sum IV - Input is a BST
  

Level Order Traversal

• 102        Binary Tree Level Order Traversal
• 107        Binary Tree Level Order Traversal II
• 339        Nested List Weight Sum
• 364        Nested List Weight Sum II
• 103        Binary Tree Zigzag Level Order Traversal
• 515        Find Largest Value in Each Tree Row
• 116        Populating Next Right Pointers in Each Node
• 117        Populating Next Right Pointers in Each Node II
• 199        Binary Tree Right Side View
• 623        Add One Row to Tree
• 637        Average of Levels in Binary Tree
  

Tree Conversion

• 114        Flatten Binary Tree to Linked List
• 536        Construct Binary Tree from String
• 108        Convert Sorted Array to Binary Search Tree
• 109        Convert Sorted List to Binary Search Tree
  

Serialization

• 572        Subtree of Another Tree
• 331        Verify Preorder Serialization of a Binary Tree
• 297        Serialize and Deserialize Binary Tree
• 449        Serialize and Deserialize BST
  

樹的題目還蠻多的，這類題目剛開始刷的時候覺得超難，腦子轉不過彎。但是慢慢理解了recursion后，就比較上手了。

前两天狗家电面有点沮丧，休息(tui fei)了几天，无论结果如何，刷题找工作还得继续，今天刷了竞赛的4题

4/23/18

Greedy

• 561        Array Partition I
• 55        Jump Game
• 45        Jump Game II
• 455        Assign Cookies
• 134        Gas Station
• 392        Is Subsequence
• 630        Course Schedule III
• 406        Queue Reconstruction by Height
• 418        Sentence Screen Fitting
• 484        Find Permutation
• 452        Minimum Number of Arrows to Burst Balloons
• 135        Candy
• 316        Remove Duplicate Letters
• 330        Patching Array
• 621        Task Scheduler
• 358        Rearrange String k Distance Apart
• 68        Text Justification
• 605        Can Place Flowers
  

4/24/18

Easy

• 342.Power of Four
• 367. Valid Perfect Square
  

Medium:

• 378. Kth Smallest Element in a Sorted Matrix
• 357. Count Numbers with Unique Digits
• 392. Is Subsequence
• 754. Reach a Number
• 134. Gas Station
  

Hard:

• 188. Best Time to Buy and Sell Stock IV
• 363. Max Sum of Rectangle No Larger Than K
• 410. Split Array Largest Sum
  

754. Reach a Number 这题有点意思，刚开始用bfs做就tle了，没想到数学能抽象到这种地步，还要很多技巧需要积累呀。

4/25/18

Easy:

• 349. Intersection of Two Arrays
• 680. Valid Palindrome II
• 441. Arranging Coins
• 359. Logger Rate Limiter
• 475. Heaters
  

Medium:

• 739. Daily Temperatures
• 362. Design Hit Counter
• 436. Find Right Interval
• 454. 4Sum II
• 333. Largest BST Subtree
  

Hard:

• 664. Strange Printer
  

475. Heaters虽然是道easy题，但是有很多细节需要注意，挺能锻炼binary search题型的技巧的

4/26/18

• 136        Single Number
• 137        Single Number II
• 260        Single Number III
• 371        Sum of Two Integers
• 191        Number of 1 Bits
• 338        Counting Bits
• 476        Number Complement
• 461        Hamming Distance
• 477        Total Hamming Distance
• 201        Bitwise AND of Numbers Range
• 318        Maximum Product of Word Lengths
• 397        Integer Replacement
• 421        Maximum XOR of Two Numbers in an Array
  

今天距离狗家电面正好一周，本来以为已经凉了，却接到了通过的电话。以后要更加努力了~

额，过了电面后换了HR，说我面试应该走校招。于是，她又发给我OA让7天内做。。电面过了还得做OA也是没谁了，最近在看OA的面经，希望题不要变呀。

5/1/2018

这几天把最近一期的contest都做了一下，速度还是慢，但是有进步的是都能做出可以accept的答案~
做完OA后一天，HR通知应该过了，以后要好好准备onsite了。

5/3/18

Add:

• 2        Add Two Numbers
• 445        Add Two Numbers II
• 67        Add Binary
• 66        Plus One
• 369        Plus One Linked List
• 415        Add Strings
  

Multiplication:

• 43        Multiply Strings
• 537        Complex Number Multiplication
• 311        Sparse Matrix Multiplication
  

Division:

• 29        Divide Two Integers
• 166        Fraction to Recurring Decimal
  

Power:

• 69        Sqrt(x)
• 367        Valid Perfect Square
• 633        Sum of Square Numbers
• 50        Pow(x, n)
• 372        Super Pow
• 231        Power of Two
• 326        Power of Three
• 342        Power of Four
  

今天参加了狗家的hangout couch session，觉得还是挺有用的，有他家的一个工程师讲解整个面试的流程以及怎么去approach一个问题，后面还有个code session让自己去写code，类似一个小小的mock了。

还有最近懈怠的有点过分了，总是困，算了还是不给自己找借口了，一个月，自己还有很多不足的地方，要达到狗家的程度的话还要加强训练。取乎其上得乎其中，取乎其中，得乎其下，取乎其下则无所得矣。