zzzzzzzy 刷题记录帖 🤓

刷题记录 之前放在自己blog 里，想了想 还是开个帖子吧~~ 嘿嘿嘿
附上 之前 刷题记录

希望每天至少5题+independent project，搞到拿到offer


### Jun 5, 2018

**LintCode:** Naive

- [x] 37. Reverse 3-digit Integer
- [x] 145. Lowercase to Uppercase
- [x] 366. Fibonacci


### Jun 12, 2018

**LeetCode:** Database

- [x] Big Countries


### Jun 14, 2018

**LeetCode:** Database

- [x] Swap Salary
- [x] Not Boring Movies
- [x] Duplicate Emails
- [x] Combine Two Tables


### Jun 15, 2018

**LeetCode:** Database

- [x] Employees Earning More Than Their Managers
- [x] Classes More Than 5 Students
- [x] Customers Who Never Order
- [x] Rising Temperature
- [x] Delete Duplicate Emails
- [x] Second Highest Salary
- [x] Exchange Seats


### Jun 16, 2018

**LintCode:** Naive

- [x] 452. Remove Linked List Elements
- [x] 454. Rectangle Area
- [x] 463. Sort Integers
- [x] 466. Count Linked List Nodes
- [x] 479. Second Max of Array
- [x] 484. Swap Two Integers in Array
- [x] 632. Binary Tree Maximum Node
- [x] 763. Hex Conversion


### Jun 18, 2018

**LeetCode:** Database

- [x] Consecutive Numbers       
- [x] Department Highest Salary
- [x] Rank Scores       


### Jul 7, 2018

**LintCode:** Binary Search

- [x] 14. First Position of Target
- [x] 141. Sqrt(x)
- [x] 159. Find Minimum in Rotated Sorted Array
- [x] 17. Subsets
- [x] 62. Search in Rotated Sorted Array
- [x] 74. First Bad Version
- [x] 75. Find Peak Element
- [x] 183. Wood Cut
- [x] 669. Coin Change

**LeetCode:** Binary Search

- [x] 69. Sqrt(x)
- [x] 33. Search in Rotated Sorted Array
- [x] 162. Find Peak Element
- [x] 322. Coin Change


### Jul 8, 2018

**SQL Exercises**

- [x] The computer store
- [x] Employee management

**LintCode:** Binary Tree `&&` Divide Conquer

- [x] **66. Binary Tree Preorder Traversal**
- [x] **67. Binary Tree Inorder Traversal**
- [x] **68. Binary Tree Postorder Traversal**
- [x] 97. Maximum Depth of Binary Tree
- [x] 480. Binary Tree Paths
- [x] 93. Balanced Binary Tree
- [x] 453. Flatten Binary Tree to Linked List


### Jul 9, 2018

**SQL Exercises**

- [x] The warehouse

**LintCode:**  Binary Search `||` Binary Tree `&&` Divide Conquer

- [x] 596. Minimum Subtree
- [x] 1219. Heaters
- [x] 28. Search a 2D Matrix
- [x] 547. Intersection of Two Arrays
- [x] 988. Arranging Coins
- [x] 457. Classical Binary Search
- [x] 60. Search Insert Position
- [x] 662. Guess Number Higher or Lower


### Jul 10, 2018

**LintCode:**  Binary Tree `&&` Divide Conquer

- [x] 595. Binary Tree Longest Consecutive Sequence
- [x] 614. Binary Tree Longest Consecutive Sequence II
- [ ] 619. Binary Tree Longest Consecutive Sequence III
- [x] 88. Lowest Common Ancestor of a Binary Tree
- [x] 376. Binary Tree Path Sum
- [ ] 246. Binary Tree Path Sum II
- [ ] 472. Binary Tree Path Sum III
- [ ] 863. Binary Tree Path Sum IV

**SQL Exercises**

- [x] Movie theatres


### Jul 11, 2018

**LintCode:**  Breadth-First-Search

- [x] **69. Binary Tree Level Order Traversal**
- [x] **70. Binary Tree Level Order Traversal II**
- [x] 433. Number of Islands
- [x] 7. Serialize and Deserialize Binary Tree
- [x] 127. Topological Sorting
- [x] 615. Course Schedule

**SQL Exercises**

- [x] Pieces and providers
- [x] Scientists
- [x] Planet Express


### Jul 12, 2018

**LintCode:**  Breadth-First-Search

- [x] 616. Course Schedule II
- [x] 242. Convert Binary Tree to Linked Lists by Depth
- [x] 71. Binary Tree Zigzag Level Order Traversal
- [x] 178. Graph Valid Tree
- [x] 137. Clone Graph
- [x] 618. Search Graph Nodes


### Jul 13, 2018

**LintCode:**  Breadth-First-Search

- [x] 598. Zombie in Matrix
- [x] 611. Knight Shortest Path
- [x] 605. Sequence Reconstruction


### Jul 14, 2018

**LintCode:**  Depth-First-Search

- [ ] 40. Implement Queue by Two Stacks


### Jul 15, 2018

**LintCode:**  Depth-First-Search

- [x] 135. Combination Sum
- [x] 153. Combination Sum II
- [ ] 564. Combination Sum IV
- [x] 136. Palindrome Partitioning
- [x] 15. Permutations
- [x] 16. Permutations II
- [x] 33. N Queens


### Jul 16, 2018

**LintCode:**  Linked List & Array

- [x] 35. Reverse Linked List
- [x] 102. Linked List Cycle
- [ ] 103. Linked List Cycle II


### Jul 17, 2018

**LintCode:**  Linked List & Array

- [x] 380. Intersection of Two Linked Lists
- [x] 36. Reverse Linked List II (dummy node)
- [x] 41. Maximum Subarray
- [x] 6. Merge Two Sorted Arrays


### Jul 18, 2018

**LintCode:**  Linked List & Array

- [x] 450. Reverse Nodes in k-Group
- [x] 105. Copy List with Random Pointer **[高频题]**
- [x] 604. Window Sum
- [x] 138. Subarray Sum
- [x] 139. Subarray Sum Closest
- [x] 372. Delete Node in a Linked List
- [x] 547. Intersection of Two Arrays
- [x] 65. **Median of two Sorted Arrays**


### Jul 19, 2018

**LintCode:**  Two Pointers

- [x] 539. Move Zeroes
- [x] 521. Remove Duplicate Numbers in Array
- [x] 415. Valid Palindrome
- [x] **31. Partition Array**
- [x] 608. Two Sum II - Input array is sorted


### Jul 20, 2018

**LintCode:**  Two Pointers

- [x] 373. Partition Array by Odd and Even
- [x] 144. Interleaving Positive and Negative Numbers
- [x] 49. Sort Letters by Case
- [x] 609. Two Sum - Less than or equal to target
- [x] 443. Two Sum - Greater than target
- [x] 8. Rotate String


### Jul 21, 2018

**LintCode:**  Two Pointers `&&` Quick Select

- [x] 461. Kth Smallest Numbers in Unsorted Array
- [x] 148. Sort Colors
- [x] 143. Sort Colors II


### Jul 24, 2018

**LintCode:**

- [x] 764. Calculate Circumference And Area






补充内容 (2018-8-2 22:56):
SQL 的“简单题”在这里 https://github.com/Zhenye-Na/SQL-Exercises

补充内容 (2018-8-3 02:46):
在 Heroku deploy 了第一个["水"]项目 https://qac.herokuapp.com/ 并且写了一个 blog https://zhenye-na.github.io/2018 ... -app-to-heroku.html

补充内容 (2018-8-3 02:52):
今天开始跟 The Web Developer Bootcamp + 做项目 ( ु•⌄• )و✧

补充内容 (2018-8-15 09:26):

webdev bootcamp 跟完啦，deploy 在这里 https://demo-mkplc.herokuapp.com/， 要在这个基础上自己增加一些其它功能 ，准备开始学 Pyspark 啦 有机不错的 proj 的点子，趁还没开学，在挣扎一下 ！！

然后是今天哒~~ 今天学习一下 新的 数据结构 Fenwick Tree / Binary Indexed Tree 用来解决 Prefix Sum 这种问题~~ 然后总结了一下放在自己的 blog 里辣

吐槽一下 lintcode 还有 隐藏题目 真的是 666


- [x] 596. Minimum Subtree (隐藏题)
- [x] 988. Arranging Coins (**Binary Search** + **Arithmetic Sequence**)
- [x] 1219. Heaters (**Binary Search**)
- [x] 840. Range Sum Query - Mutable (**Fenwick Tree / Binary Indexed Tree**)



补充内容 (2018-9-23 14:52):
踩个鸡儿？爱看不看好嘛？？？

肥宅快乐水 发表于 2018-8-3 00:42
为什么只更新到7/244

呼 自己默默搬家+做项目 这就补上

今天做 3Sum 的时候 第一反应没有想到 用 2Sum 来解决而是用 Binary Search 来去找中间那个数，但是发现 “自己能力不足，代码写出来又臭又长，过不了”挂出来接受各位大佬批评指正！！
还希望各位能够看一下，指出自己写的错误的地方！！

下面贴上代码


Binary Search + Two Pointers

代码思路是这样的

• 首先排序，不然没办法判断多了还是少了
• 然后取出 头尾，在中间 Binary Search 一下，找到了就返回 `index`，找不到就返回 `-1`
• 然后就要移动 头尾指针，因为会有重复，所以有一个“象征性去重”的过程
  

1. public class Solution {
   
2.     /**
   
3.      * @param numbers: Give an array numbers of n integer
   
4.      * @return: Find all unique triplets in the array which gives the sum of zero.
   
5.      */
   
6.     public List<List<Integer>> threeSum(int[] numbers) {
   
7.         // write your code here
   
8.         List<List<Integer>> result = new ArrayList<List<Integer>>();
   
9.         if (numbers == null || numbers.length < 3) {
   
10.             return result;
    
11.         }
    
12. 
    
13.         Arrays.sort(numbers);
    
14.         int start = 0, end = numbers.length - 1;
    
15.         while (start < end) {
    
16.             List<Integer> combination = new ArrayList<>();
    
17. 
    
18.             int target = 0 - (numbers[start] + numbers[end]);
    
19.             int idx = binarySearch(numbers, target, start, end);
    
20. 
    
21.             if (idx != -1) {
    
22.                 combination.add(numbers[start]);
    
23.                 combination.add(numbers[idx]);
    
24.                 combination.add(numbers[end]);
    
25.                 result.add(combination);
    
26.                 start++;
    
27.                 while (start >= 0 && numbers[start] == numbers[start + 1]) {
    
28.                     start++;
    
29.                 }
    
30.                 end--;
    
31.                 while (end <= numbers.length - 1 && numbers[end] == numbers[end - 1]) {
    
32.                     end--;
    
33.                 }
    
34.             } else {
    
35.                 if (-target < 0) {
    
36.                     start++;
    
37.                 } else {
    
38.                     end--;
    
39.                 }
    
40.             }
    
41.         }
    
42. 
    
43.         return result;
    
44.     }
    
45. 
    
46. 
    
47.     private int binarySearch(int[] nums, int target, int start, int end) {
    
48. 
    
49.         while (start + 1 < end) {
    
50.             int mid = (end - start) / 2 + start;
    
51. 
    
52.             if (target == nums[mid]) {
    
53.                 return mid;
    
54.             } else if (target < nums[mid]) {
    
55.                 end = mid;
    
56.             } else {
    
57.                 start = mid;
    
58.             }
    
59.         }
    
60. 
    
61.         if (target == nums[start]) {
    
62.             return start;
    
63.         }
    
64. 
    
65.         if (target == nums[end]) {
    
66.             return end;
    
67.         }
    
68. 
    
69.         return -1;
    
70.     }
    
71. 
    
72. }

复制代码

Input
[-8,-8,-8,-5,-4,-1,-1,0,1,2,3,4,5,7]

Output
[[-8,1,7],[-8,3,5],         [-5,1,4],                            [-4,1,3],[-1,-1,2]]

Expected
[[-8,1,7],[-8,3,5],[-5,0,5],[-5,1,4],[-5,2,3],[-4,-1,5],[-4,0,4],[-4,1,3],[-1,-1,2],[-1,0,1]]


根据输出可以发现问题所在，以`-8`开头，`5`结尾的找到之后，会 `start++`，`end--`，然而 存在另一个仍然以`5`结尾的解，被程序直接跳过了

为什么只更新到7/244

Update:

### Aug 6, 2018

**LintCode:** Data Structure `&&` Dynamic Programming

- [x] 517. Ugly Number


### Aug 7, 2018

**LintCode:** Tag: Basic Implementation

- [x] 30. Insert Interval
- [x] 55. Compare Strings
- [x] 9. Fizz Buzz
- [x] 170. Rotate List
- [x] 13. Implement strStr()
- [x] 78. Longest Common Prefix


Related Problems:

- [ ] 156. Merge Intervals


### Aug 8, 2018

**LintCode:** Tag: Binary Search

- [x] 548. Intersection of Two Arrays II
- [x] 61. Search for a Range **Binary Search integrates First Position and Last Position together**
- [x] 76. Longest Increasing Subsequence **Dynamic Programming `||` Binary Search**
- [x] 160. Find Minimum in Rotated Sorted Array II **Binary Search `&&` Two Pointers**

祝贺自己成功刷完了人生中第100题 233，自己做了excel表格记录

补充内容 (2018-8-9 12:28):
github: https://github.com/Zhenye-Na/LxxxCode

### Aug 9, 2018

**LintCode:** Ladder - String

- [x] 171. Anagrams
- [x] 158. Valid Anagram
- [x] 1038. Jewels and Stones
- [x] 77. Longest Common Subsequence **Dynamic Programming**
- [x] 79. Longest Common Substring **Dynamic Programming**


今天学习到的知识点有：

Java

• ArrayList<>() and LinkedList<>()
• ArrayList remove() method
• compare a string with the empty string ("") in java
• String.toCharArray()
• String.valueOf()
• Map.entrySet()
• entry.getValue()
• ArrayList.addAll()
  

Python

• collections.Counter()
  

推荐两个 Youtube Channel

• Tushar Roy 主要是白板讲解 interview questions，是真的**讲解**
• Interview Questions playlist by Byte By Byte 我觉得讲的还可以 适合我
  

### Aug 10, 2018

**LintCode:** Ladder - Integer Array

- [x] 100. Remove Duplicates from Sorted Array
- [x] 101. Remove Duplicates from Sorted Array II
- [x] 172. Remove Element
- [x] 50. Product of Array Exclude Itself
- [x] 189. First Missing Positive
- [x] 54. String to Integer (atoi)

**LeetCode:** Database

- [x] 577.Employee Bonus

从昨天就已经开始练习 首先在白纸 （没有白板）写思路，过程，需要考虑的东西，今天看了个视频 可能对转专业越来越不友好了，定个目标刷他个 400 题吧

加油！

### Aug 11, 2018

**LintCode:** Ladder - Integer Array

- [x] 64. Merge Sorted Array
- [x] 56. Two Sum

今天听了 linghuchong 的公开课。。。要不要换成Python刷题， 啊 纠结！

今天又改了一下简历，挂在地里了

加油加油！

### Aug 12, 2018

**LintCode:** Ladder - Integer Array

- [x] 57. 3Sum
- [x] 59. 3Sum Closest
- [x] 31. Partition Array
- [x] 139. Subarray Sum Closest
- [x] 58. 4Sum

从明天开始抛弃 Java 改用 Python 刷题啦~

这是按照什么顺序刷滴