刷题贴 一年经验

2018.03.25  154 题

补充内容 (2018-4-8 05:05):
居然有人加米！太感谢了

这次h1b被lay 刷题找工作圆满结束，历时两个半月
Passed:
1. Coupang,   120k base, 20k sign on, 10k stock
2. Microsoft,  120k base,  30k sign on, 90k stock, bonuse 20% base + 9k stock
3.Cisco Tetration, 145k base, 200k stock
4. Bloomberg, 160k base, 25k bonus, 25k sign on

Waiting:
1. Google
2. C3 IOT

Failed:
1. Opendoor
2. Another team in bloomberg
3. Groupon
4. segment

Canceled:
1. Goldman saches
2. Uber
（实在面不动了。。。uber还是很好的，以后有缘再面了）

请教一下楼主刷题的方法，楼主是自己想，自己写，再看答案？还是直接看答案的？

楼主真是太勤奋了，祝好运！！

紫薯紫薯

110. Balanced Binary Tree   
      Key point: dfs to calculate depth. Handle unbalanced subtree with different depth can improve performance
540. Single Element in a Sorted Array
     Key point : "sorted". If it's not sorted, hashset might be the best solution. but if it's sorted, binary search is only log(n);
108. Convert Sorted Array to Binary Search Tree
     Key point: recursive

2018.3.26  156题
347. Top K Frequent Elements
     key points: if time complexity can be O(NlogN), we can use priority queue, treeMap; but it requires less time complexity, so use bucket to store frequency would meet the requirement

268        Missing Number
    WTF....

541. Reverse String II
557. Reverse Words in a String III
       No need to consider more than more space between tow words or the start is space... The problem is easy
228. Summary Ranges
       No data structure. Don't think it will be asked in interview

433. Minimum Genetic Mutation
       Completely misunderstood this problem....It's a really good BFS problem. Should practice it again later
256. Paint House
265. Paint House II
       How to decrease time complexity and space ? When DP doesn't need every old status, no need to use too much space.
276. Paint Fence
       Super smart
312. Burst Balloons
       WTF... DP so difficult to understand
167. Two Sum II - Input array is sorted
      two pointer

till today ： 164题  

2018.03.27
上班感觉也不能什么也不干， 下午五点开始刷

349        Intersection of Two Arrays   
142. Linked List Cycle II
    draw it and do some math
229. Majority Element II
    Moore voting. Don't make initial value the same!!
287. Find the Duplicate Number
     same algorithm as 142, but hard to think of it.
383. Ransom Note
      easy..
728. Self Dividing Numbers
      easy, no fancy solutions

24. Swap Nodes in Pairs
     recursive solution is elegant! but not useful in prod
189. Rotate Array
    same as rotate matrix problem! rotate twice will solve it elegantly
69. Sqrt(x)
    binary search!
448. Find All Numbers Disappeared in an Array
     some tricks about index and the value if they are both in the same range. Saw this kind of problems before
387. First Unique Character in a String
     actually we can still use int[26]. Hashmap space complexity too high
73. Set Matrix Zeroes
     In place!

2018.03.28
at the beginning of today: 173 problems solved
89. Gray Code
     It's very simple if you understand the logic.
73. Set Matrix Zeroes
   weird

279. Perfect Squares
      DP and BFS
572. Subtree of Another Tree
      when two vals equal and check subtree, should be the same tree not subtree. So need another helper method
4. Median of Two Sorted Arrays
     The O(long(min(m,n))) is so hard to consider all the edge cases
295. Find Median from Data Stream
    data structure!

2018.03.29  183

2018.03.31  186