Happygirlzt: LeetCode入门（漫谈常见题型与解法）

 Here is the link. 

I will spend 30 minutes to watch the video Sunday morning. I will do that first thing in the morning. 

Arrays

• Two pointers (sliding window)
• Binary search ( sorted, search space)
• Combined with Map 
• Prefix sum ( DP )
• Quick select (kth ...)

Stacks

   familiar with some monotonic stack questions

• Maximum rectangle
• Next greater elements
• Trapping rain water - optimal, two pointers

   

   Next 

Queue  BFS

Graphs   BFS, DFS, Dijkstra's

Backtracking 

• permutation - all possibilities
• subsets
• combination sum
• partition equal
• subset sum
• N-Queen
• Sudoku

Dynamic programming

•  total ways
• True/ False
• max/ min

• 0/1 Knapsack
• perfect squares
• Coin changes - total ways, minimum
• climbing stairs 
• decode ways
• string related
• regular expression matching
• wildcard matching
• Edit distance
• LIS / LCS
• 2D matrix
• maximum square
• range sum query
• bomb enemy
• unique paths, total ways
• greedy  Heap (sort)  
• Top K
• Campus bikes
• merge k sorted lists
• 
  
• 
  
• 
  

Leetcode discuss

Sept. 13, 2018

Introduction

The following content is the copy of my page on github. The link is here. 

It takes a village to raise a child.

I like to adapt the culture to learn and contribute to Leetcode discuss community. It is so easy to learn from so many ideas, but it takes me more than 3 years five months to understand that I also should learn to contribute to the community.

I like to see if I adopt the value "It takes a village to raise a child", as a programmer, I think that in order to get smart, I have to learn to contribute Leetcode discuss. Since I find that it is so easy to learn the algorithm on leetcode discuss, I like to be one of them to work hard and share the thoughts and hard work.

This page is dedicated to show my effort to provide a feature to review all my past practice, all my sharing on Leetcode discuss.

It is time for me to share my practice on Leetcode.com discussion panel.

I like to encourage myself to share my code on Leetcode discussion. I learn so many things from those people sharing on Leetcode discussion panel. I like to be one of them.

Leetcode discuss

I will share more practice later. I also will add those links I shared before.

Sept. 9, 2018

Leetcode.com does not provide product feature to look up discuss shared by a player. Google search result will only show at most 20 results of my discuss.

Google search: Leetcode leetcode jianmin.chen.39

Here is the link.

Sept. 13, 2018

I like to list all my sharings on Tree easy level algorithms, Array easy level algorithms, Math easy level algorithms.

Tree easy level algorithms (solved 30)

437 Julia's discuss link
501. Find Mode in Binary Search Tree
590. N-ary tree postorder traversal
671. Second minimum node in a binary tree
687. Longest univalue path

Array easy level algorithms (solved 44)

53: Maximum subarray
119: Pascal's triangle II Naive one
119: Pascal's triangle II Optimal one
169. Majority element
189. Rotate the array
219. Contains Duplicate II
414. The third maximum number
485. Max Consecutive Ones
448. Find All Numbers Disappeared in an Array
566. Reshape the Matrix
624. Maximum distance in arrays I will study the blog and write one.
628: Maximum product of three numbers
661: Image smoother
665. Non-decreasing array
695. Max Area of Island
717. 1-bit and 2-bit characters
724. Find pivot index
746: Min cost climbing stairs
766. Toeplitz Matrix
830: Positions of large groups
832. Flipping an Image
840. Magic Squares In Grid
867. Transpose matrix - pass 29/36 test cases
888. Fair Candy Swap
896. Monotonic Array

Math easy level algorithms (solved 18)

7. Reverse integer
9. Palindrome number
168. Excel Sheet Column Title
172: Factorial trailing zeroes
367. Valid Perfect Square
400. Nth Digit
441. Arranging Coins
507. Perfect number
633. Sum of square numbers

Medium level (solved 53)

109. Convert sorted list to binary search tree
684. Redundant Connection

Hard level (solved 33)

239. Sliding Window Maximum
optimal solution using LinkedList

My own blogs

Leetcode 437

Leetcode 501

Leetcode 746: Min cost climbing stairs

August 30, 2018

Introduction

It is an easy level algorithm and I wrote a solution using dynamic programming.

My practice

I need to write a few sentences to summarize my approach and then share the code. Here is my sharing on Leetcode discuss.

weekend planning - easy level array algorithm

July 28, 2018

Introduction

It is time for me to solve as many easy level algorithms as possible. So I can review my last two week practice and I will be so happy to know that I solve 50 algorithms in last two weeks, and also I work full time 80 hours last weeks.

It is not easy to move on next algorithm quickly. In order to do that, I have to train myself focus on analysis and coding. Cut emotional baggage for each algorithm, how I feel, what my concerns, I should learn quickly and move forward with another problem solving.

Easy level array algorithms

I like to list those algorithms here. I like to solve 10 easy level array algorithms this weekend. The number of easy level array algorithms is around 45 to 50.

665	Non-decreasing Array	19.9%	Easy
	189	Rotate Array	26.3%	Easy
	414	Third Maximum Number	28.2%	Easy
	532	K-diff Pairs in an Array	28.4%	Easy
	581	Shortest Unsorted Continuous Subarray	29.4%	Easy
	605	Can Place Flowers	30.0%	Easy
	88	Merge Sorted Array	32.8%	Easy
	219	Contains Duplicate II	33.3%	Easy
	840	Magic Squares In Grid	34.3%	Easy
	624	Maximum Distance in Arrays	35.8%	Easy
	26	Remove Duplicates from Sorted Array	37.3%	Easy
	643	Maximum Average Subarray I	37.8%	Easy
	849	Maximize Distance to Closest Person	38.1%	Easy
	1	Two Sum	38.6%	Easy
	724	Find Pivot Index	39.2%	Easy
	119	Pascal's Triangle II	39.3%	Easy
	66	Plus One	39.9%	Easy
	35	Search Insert Position	40.0%	Easy
	747	Largest Number At Least Twice of Others	40.4%	Easy
	53	Maximum Subarray	40.8%	Easy
	118	Pascal's Triangle	41.3%	Easy
	27	Remove Element	41.5%	Easy
	674	Longest Continuous Increasing Subsequence	42.7%	Easy
	746	Min Cost Climbing Stairs	43.8%	Easy
	121	Best Time to Buy and Sell Stock	43.8%	Easy
	628	Maximum Product of Three Numbers	44.8%	Easy
	268	Missing Number	45.7%	Easy
	830	Positions of Large Groups	46.7%	Easy
	661	Image Smoother	46.8%	Easy
	697	Degree of an Array	47.0%	Easy
	167	Two Sum II - Input array is sorted	47.4%	Easy
	217	Contains Duplicate	48.1%	Easy
	122	Best Time to Buy and Sell Stock II	48.6%	Easy
	169	Majority Element	49.0%	Easy
	717	1-bit and 2-bit Characters	49.0%	Easy
	448	Find All Numbers Disappeared in an Array	51.3%	Easy
	283	Move Zeroes	52.1%	Easy
	695	Max Area of Island	52.2%	Easy
	485	Max Consecutive Ones	53.8%	Easy
	243	Shortest Word Distance	54.2%	Easy
	566	Reshape the Matrix	57.7%	Easy
	766	Toeplitz Matrix	58.2%	Easy
	561	Array Partition I	66.8%	Easy
	867	Transpose Matrix	66.8%	Easy
	832	Flipping an Image	69.2%	Easy