From January 2015, she started to practice leetcode questions; she trains herself to stay focus, develops "muscle" memory when she practices those questions one by one. 2015年初, Julia开始参与做Leetcode, 开通自己第一个博客. 刷Leet code的题目, 她看了很多的代码, 每个人那学一点, 也开通Github, 发表自己的代码, 尝试写自己的一些体会. She learns from her favorite sports – tennis, 10,000 serves practice builds up good memory for a great serve. Just keep going. Hard work beats talent when talent fails to work hard.
Friday, July 31, 2020
Stanford university: CS144 – Introduction to Computer Networking
Stock purchase: My purchase of TFSA and Key largo portfolio
Introduction
Analysis and my monthly plan on August 2020
My business plan
Actionable items
Exxon, Chevron Earnings Gutted by Virus-Driven Demand Slump
Exxon Mobil Corp. and Chevron Corp. posted the worst losses in a generation after the pandemic and a global crude glut combined to batter almost every part of their businesses.
Exxon’s $1.1 billion second-quarter loss was the deepest in the company’s modern history. A collapse in crude prices bled the company’s production division while Covid-19 lockdowns lowered demand for everything from jet fuel to plastic wrap, hobbling the company’s refining and chemical units.
Chevron recorded its weakest performance in at least three decades and warned that the global pandemic wreaking havoc upon energy markets may continue to drag on earnings. The explorer plans to curtail the equivalent of 5% of its worldwide output during the current quarter and backtracked on plans to massively ramp up production from its prized Permian Basin holdings.
Oil has become the poorest-performing sector of U.S. equity markets as a confluence of economic, political and structural threats coalesce to imperil the very foundations of the petroleum industry. Sweeping layoffs, budget cuts and project cancellations haven’t been enough to arrest the industry’s decline as fleeing investors made energy the worst investment in the S&P 500 Index this year.
Without the massive trading operations that shielded European oil explorers such as Royal Dutch Shell Plc and Total SE from losses, Chevron was exposed to the full force of this year’s oil price rout. Notably, Exxon’s nascent trading foray “experienced unfavorable mark-to-market derivative impacts,” the company said.
Exxon generated zero cash from operating activities during the quarter, according to a statement on Friday.
Actionable Items
Buy some Exxon stock.
Big Tech Got Bigger, Big Oil Got Smaller During Virus Lockdown
Thursday, July 30, 2020
More distributed courses please!
Introduction
System design preparation
AMD stock: 50% return July 2020 - I missed it!
Introduction
My AMD stock research
CVE stock: Probability analysis
- There is a chance for second crash in short future. No one can avoid market risk;
- The lowest price is 5.89. Should I wait for the price? Or I just go for 6.09?
- How much should I take risk? Should I purchase 10,000 shares or 1000 shares?
- Market swing is the chance to make 10% return.
- Admit that I am a beginner. Try to survive longer. I save those TFSA funds over 10 years.
- Be patient. Do not gamble! Take some risk as well.
GE post $2 billion loss as jet engine orders sink
General Electric Co. posted a roughly $2 billion quarterly loss as revenue tumbled 24%, hurt by a steep decline in a jet-engine business that has been hobbled by the coronavirus pandemic.
The aviation business, once a profit engine for GE, swung to a loss in the June quarter as both revenue and orders plunged. The unit produces engines for Boeing Co. and Airbus SE planes but has had to cut production and jobs as airlines delay orders. On Wednesday, Boeing said it would cut further production of commercial jets.
GE reported it burned through less cash in the June quarter than it had previously warned. The company reported adjusted negative cash flow from industrial operations of $2.1 billion, compared with its projection of negative $3.5 billion to $4.5 billion in May. Analysts were expecting negative cash flow of $3.29 billion, according to FactSet.
"We're working through a still-difficult Covid-19 environment," said CEO Larry Culp, adding that he still expected a prolonged recovery for the commercial-aviation business. "Still, based on what we see today and the actions we've taken, sequential improvement in earnings and cash in the second half of the year is achievable."
Umich.edu: Introduction to distributed system
- Resource sharing
- Device sharing
- Flexibility to spread load
- Incremental growth
- Cost/performance
- Reliability/Availability
- Inherent distribution
- Security?
University of Waterloo: Distributed Database
HSE.TO stock: Husky Energy swings to $304-million loss in Q2 as revenues plunge
CALGARY — Husky Energy Inc. swung to a $304-million net loss in the second quarter as revenues plunged nearly 55 per cent.
The Calgary-based oil producer says it lost 31 cents per diluted share for the three months ended June 30, compared with net income of 36 cents per share or $370 million a year earlier.
Revenues were $2.38 billion, down from $5.24 billion in the second quarter of 2019.
Husky Energy was expected to lose 39 cents per share on $2.73 billion of revenues, according to financial markets data firm Refinitiv.
Funds from operations were $18 million or two cents per share, down from $802 million or 80 cents per share a year earlier while capital expenditures were $310 million, including $63 million in Superior Refinery rebuild capital.
Total equivalent production fell 7.8 per cent to 247,000 barrels of oil equivalent per day, from $268,000 a year earlier.
Facts to review:
Wednesday, July 29, 2020
10 reasons I will be rich
10 reasons I am not rich
Introduction
10 reasons I am not rich
Search Results Web results Leonard Kleinrock - Wikipedia
What makes a good researcher?
System design: Computer networking - a top-down approach 7th edition
Why Kodak Stock Skyrocketed 203% Today
Kodak Stock Up More Than 1,000% On Deal To Produce Generic Drug Ingredients
Tuesday, July 28, 2020
System design: What is a reverse proxy server?
I like to put together my notes:
A proxy server is a go‑between or intermediary server that forwards requests for content from multiple clients to different servers across the Internet. A reverse proxy server is a type of proxy server that typically sits behind the firewall in a private network and directs client requests to the appropriate backend server. A reverse proxy provides an additional level of abstraction and control to ensure the smooth flow of network traffic between clients and servers.
What is a proxy server?
A proxy server
a go‑between or intermediary server
forward requests for content
from multiple clients to different servers across the Internet.
Where is a proxy server to stay?
A reverse proxy server
a type of proxy server
typically sit behind the firewall in a private network
direct client requests to the appropriate backend server.
What is a proxy server? Explain using your own words.
A reverse proxy
an additional level of abstraction and control
the smooth flow of network traffic between clients and servers.
Additional layer of abstraction and control
Sunday, July 26, 2020
System design: How to prepare myself to be a best learner?
Introduction
It is my short research about how to be a best learner on system design next two weeks. It is not easy, but I like to put together some creative ideas.
Facebook system design
I like to look up Leetcode system design tagged with Facebook.
Follow up on July 27, 2020
Facebook onsite: Study topics
Introduction
It is important for me to review and learn those topics very well in next two to three weeks. I need to make a complete check list and ensure that I can understand the basics.
Topics to review
Some topics you should be familiar with:
- Concurrency (threads, deadlock, starvation, consistency, coherence)
- Networking (IPC, TCP/IP)
- Abstraction (understanding how OS, filesystem, and database works)
- Real-world performance (relative performance RAM, disk, your network, SSD)
- Availability and Reliability (durability, understanding how things can fail) -Data storage (RAM vs. durable storage,
compression, byte sizes)
- CAP Theorem
- Byte math
INFRASTRUCTURE & OPERATIONS - Painless container management with GKE & Kubernetes
Brendan Burns - Microsoft Distinguished engineer
Introduction
It is my short research about the author of book I am reading second day. It is called "Designing distributed systems - Patterns and paradigms for scalable, reliable services".
Brendan burns
I spent one hour to go over the book and see if I can learn something quickly. System design interview preparation is the art, and I do like to take some risk this time for hunting for good learning material, asking friends, and get connected to people in my social circle.
I asked my friend who works at NVIDA senior machine learning engineer, Dr. Liu recommended me the book.
Facebook onsite: Preparation - ask a friend
Introduction
My notes
Focus on algorithm. It is hard to remove bias from system design interview. Make sure that I can solve all the algorithm problems on onsite interviews.
System design: Ask a friend
Introduction
A system design book
Brendan Burns
Linkedin Liu Xin - Here is the link.
Good job! Dr. Liu!
CAP theorem - P is tough to remember - Partition tolerance
Saturday, July 25, 2020
Sharding & IDs at Instagram
With more than 25 photos and 90 likes every second, we store a lot of data here at Instagram. To make sure all of our important data fits into memory and is available quickly for our users, we’ve begun to shard our data — in other words, place the data in many smaller buckets, each holding a part of the data.
Friday, July 24, 2020
INTC stock: Learn to be a smart investor
Introduction
Analysis
Intel (Intc) is likely to open at $57 range and trading between $56 low to $59 low possibly $60.
If you look at the history of Intel after earnings, for example Q1'2020 earning released after hours on 4/23/20 at 2PM Pacific time, the after hours trading price dropped almost -7% after hours from closing price of $58.7 to $54.9 after hours.
INTC stock: Learn more about business
Introduction
It is tough for me to catch up more about Intel business. So I went to Yaoo->Finance->Conversation underneath stock page.
INTC stock
I like to review intel stock and learn more about the following content:
Intel expecting to make over $4 per share for 2020, what is the issue here? A delay while no one can afford chips and upgrades currently is not all that bad of a deal. Balance sheet looks like INTC has double the assets to liabilities by about 70 billion.
Intel also has made over $20 earnings over last 10 years than what it is currently trading which should all be in the bank. There are double the assets to liabilities. We are talking about 70 billion vs AMD 3 billion on the balance sheets.
AMD market cap is close to 80B
INTC market cap is close to 200B
Intel has AMD's market cap in asset value.
Is my analysis correct?
Intel expecting again $4.50 about this year as it raised guidance a little, it just wont have the latest chips ready till next year. I think next year is a better time to release the chips.
AMD $3B of assets which will grow some however trading 20x assets minus liabilities.
INTC is trading about 3x Assets to liabilities.
No brainer this is getting given away at todays price. IMO today is a buy around $50 easy. Intel researches, develops and sells other technologies other than CPU's.
The above is just an investor's analysis.
My favorite comments:
Lost 40 BILLION in valuation while delivering great earnings. Zero patience in this market due to momentum based trading algos.
Actionable Items
July 29, 2020
I did research on Lisa su and also AMD stock early in July, my hidden jealous was not so good and it affected my decision making. Now my position of Intel stock has 7% loss. I should purchase half of AMD to support Lisa Su and AMD instead.
Interviewing.io system design show case:
Introduction
It took me near one hour to watch one of showcase on interviewing.io. I like to write down some notes about the showcase interview.
Showcase of system design.
I will add more later.
Facebook onsite: Three weeks learner - Amazing learner
Introduction
Three weeks learner
INTC stock: 15% plunge of Intel stock
Introduction
It is my favorite company Intel and the stock. I did make purchase today.
INTC 170 shares
Thursday, July 23, 2020
Wednesday, July 22, 2020
System design advice: 10 - 15 popular system design questions
Leetcode 1040: Longest duplicate string
Longest duplicate string is binary search with hash
Binary search for the length, use Robin karp hash
Question about Leetcode 1040:
- I found this one helpful for Robin, thank you for sharing. You are the expert
There is no pattern string, how to find which one to compare. Save all the same length one in the hashset? Rabin hash is to compare to given a pattern string.
Here is my gist saved. I will play Java code and see how it works.
System design: Youtube channel recommendations
Introduction
It is day one again for my system design study. I also need to ask friends on Linkedin.com first. I met them as an interviewer.
VMWARE engineer's recommendation
There is another one by Gaurav Sen. you can check that as well. But Tech Dummies has really good stuff. He explains well.
- Additionally there is a system design channel on YouTube by Narendra. You can follow that.
- It’s call tech dummies
Weekend marathon on Leetcode mock interview phone screen
It is so important for me to work on my crafting skills. I started marathon to work on Leetcode mock interview phone screen last Friday evening.
My marathon
I am not sure how many algorithms I can complete in weekends. I have 5 mock interviews. So far, I completed over 10 algorithms.