寒假刷题打卡

秋招不顺，圣诞假期准备坚持刷题并且补C++ Java 和 Database 的基础，以备战狗家电面及春招。每天目标

• 4-5题/天
• 1h公开课
• 1h语言基础（C++ primer, Fluent Python, Effective Java)
• 锻炼30min+
• 日期:12/23 - 1/20
  

元旦休息到3号，这几天的进度update一下
Binary Index Tree & Segment Tree   
    同学写的笔记

Java GC
    怎么在面试时回答Java垃圾回收机制（GC）相关问题？ - 刘成的回答 - 知乎


Binary Search

    LC69 & 367 Sqrt. 还可以了解下牛顿迭代法
    LC167 最简单的2sum
    LC81 deal with duplicate
    LC287 既可以binary search，还有一种类似detect cycle的解法

Trie
    据说FB常考
    LC208 implement trie
    LC79 & 212 Word Search. 好题. DFS + Trie

Decode & Encode
    91 394 & 471; LC471在去年的面经中看到，变态的DP，如果要优化还可以考KMP...最优解好像是(str + str).indexOf(str)去检查str是否由某些substr重复得到

此外LC355. Design Twitter. 在一个群里看到一位quant大佬的个人网站，复习了怎么证明中心极限定理，莫斯科国立物理PhD + Courant数学PhD....

12/22
LC215. Quick Select, O(N)
LC214. Brute Force, 最后一个case ETL; KMP s+'#'+s[::-1]; Recursive
LC207. Detect Cycle
LC210. topological sort

Java
default method in interface: implementation of that method can be provided in the same interface, without affecting the classes implementing the interface

arraylist vs linkedlist:  dynamically re-sizing array vs doubly-linked list.
linkedlist:
get(index) O(n/4);    add(elt) O(1);    add(index, elt) O(n/4)    remove(index) O(n/4)
arraylist:
get(index) O(1);    add(elt) O(1);    add(index, elt) O(n/2)    remove(index) O(n/2)

12/23
LC394 stack
LC267 backtracking; transform to solve permutation II
LC479 math
LC5 DP or iterative
LC47 Permutation II
LC669 recursive

Java
Overriding vs Overloading
Overrrinding: two methods with same method name and parameters. One method is in parent class, the other in child class
Overloading: same method name but different parameters
Polymorphism applies to overriding, not overloading; Overriding is a run-time concept while overloading is a compile concept
Constructor
not inherited but start with a call to one of the super class's constructors





补充内容 (2017-12-24 12:39):
<a href="http://igstan.ro/posts/2011-09-09-how-inheritance-violates-encapsulation.html" target="_blank">Inheritance breaks encapsulation</a>

补充内容 (2017-12-24 12:53):
Casting Poodle largePoodle = (Poodle) maxDog(frank, frankSr)

补充内容 (2017-12-24 13:07):
Higher Order Function before Java 7 by abstract method in interface

我也开始花钱在UDEMY 上学课。找了好几个月工作，很不顺。结果也没复习旧的，没学新的。终于觉得这样下去要完蛋。今天开始看VEDIO学习了。人生好难啊。

我也开始花钱在UDEMY 上学课。找了好几个月工作，很不顺。结果也没复习旧的，没学新的。终于觉得这样下去要完蛋。今天开始看VEDIO学习了。人生好难啊。

12/24
LC697
LC205
LC131 最优解值得参考
LC680
LC409
LC266
easy题做起来没什么感想....

楼主这强度够大的

12/25
LC65 valid number, many testcases, best solution shows how to catch float number, educational
LC318 bit manipulation, very good problem, ord() vs chr()
LC734
LC737 Union Find 参考LC323

LC695 equal to Number of Island
LC694  how to depict shape of islands
LC720 ...没做出来真是蠢 题目不错
LC521 烂题
LC594

Python
nonlocal vs global
nonlocal refer to previously bound variables in the nearest enclosing scope excluding globals


Java
autoboxing(auto-unboxing)
implicit conversions between wrapper/primitives