Thursday, October 26, 2023

Leetcode | Tree algorithm | Medium level | Unsolved | Leetcode premium

 143/219 problems solved. 40 medium level tree algorithms to solve


1485
1676
1506
2415
427


1325
1522
1666
2196
1612
1586
2445
1740
2641
2764
1457
2477
1120
1257
1600
1443
156
2471
1644
1273
1245
510
2378
2385
2368
2673
1609
1519
298
549
558
2467
1339
2049
1993
1902
333
2476

Linkedin | Blogger Jianmin Chen

Here is the link.


Wednesday, October 25, 2023

Cascade Falls Regional Park

 Cascade Falls Regional Park is a regional park under the administration of the Fraser Valley Regional District in the Hatzic Valley of the Lower Mainland region of British Columbia, Canada. The park was originally 9.5 hectares in area but was expanded to a current 22 hectares. It has picnic tables and pit toilets, with various hiking trails and a walkway leading to a viewing platform over a large waterfall, which is 15 minutes walk from the park's parking lot.

The falls and their associated park have the following features:

  • 30-metre waterfall
  • Suspension bridge spanning Cascade Creek
  • Viewing platforms on either side of the suspension bridge
  • 1 km trail featuring stairs through coniferous forest
  • Small run of waterfalls dropping 18 metres into tranquil lower pools[1]

It is located in the McConnell Creek area northeast of Mission. Cascade Creek was formerly named McConnell Creek, after a logger in the area called Jack McConnell, who in fact had changed his name from John Connell further to the failure of his logging business.[2] Cascade Creek drains into the southeast end of Stave Lake southwest of Davis Lake Provincial Park.[3]

The park was first proposed in 1984 via studies commissioned by the Dewdney-Alouette Regional District and officially inaugurated on June 7, 1986. The park is open from 7AM till sunset, throughout the year.[4]

Cascade Falls was featured in the final scene of the film Big Bully, as the location of a fight between characters played by Tom Arnold and Rick Moranis.


Oct. 25, 2023 

Chestnuts trees inside the park 


Google map 

Cascade Falls Regional Park, 36421 Ridgeview Rd, Deroche, BC V0M 1G0

Weaver Creek Spawning Channel, 17780 Morris Valley Rd, Agassiz, BC V0M 1A1

Linkedin | Hao Xu | Top player | Ph.D.

 

https://leetcode.com/hxu10/

I am a Computational physics PhD recipient in the College of William and Mary. The graduation date was August 26th, 2022.
I am currently looking for jobs like quant, software develop engineer, data scientist. It will be more than welcome that you can refer me.

Github link: https://github.com/hxu10
Programming: python, shell, fortran, C, C++
Web development: Html, css, javascript

Rank 551 in 2022 Google Code Jam round 3 (about 100k registraints)
Rank 836 in 2023 Facebook Hacker cup round 2.
Rank 11 in leetcode weekly contest 317.

Hobbies: Running 10+ full marathons.I am a Computational physics PhD recipient in the College of William and Mary. The graduation date was August 26th, 2022.

Tuesday, October 24, 2023

Convoy | Technology firm

Linkedin | Liang Chen 

Senior Director of Engineering

Senior Director of Engineering
Convoy Inc · Full-timeSep 2021 - Oct 2023 · 2 yrs 2 mosSeattle, Washington, United States · On-site

Convoy | Shutdown

 Convoy went through four rounds of layoffs over the past year to help cut expenses. Other logistics startups that surged during the pandemic, such as Flexport and Flexe, have also laid off staff.

Before this week, Convoy had around 500 employees, down from a peak of about 1,500 people.

Founded in 2015 by two former Amazonians, Lewis and Grant Goodale, Convoy raised around $1 billion from a who’s-who list of investors that included Bill Gates, Jeff Bezos, Marc Benioff, former U.S. senator Bill Bradley, and even Bono and The Edge from U2 fame.

The company was valued at $3.8 billion after raising $260 million last year, which included $100 million from venture debt investor Hercules Capital. Convoy also secured an additional $150 million line of credit from J.P. Morgan at the time.

The Information reported that Convoy ultimately ran out of cash after revenue projections fell well short of expectations this year, and won’t be returning any money to equity investors. Hercules Capital is trying to sell off Convoy’s assets, according to The Information.

“I was hoping for a different and better outcome for you,” Lewis said on the call. “Because I think this is one of the most high-caliber, low-asshole ratios I’ve ever worked with, in this company. There’s just awesome fucking people here. And we built something that’s so incredible.”

Convoy collapse

 Convoy raised $260 million at a $3.8 billion valuation just 18 months ago. Now the company is shutting down. (GeekWire File Photo)

Convoy’s plan to transform the trucking industry has come to a screeching halt.

The Seattle company is closing its core business and laying off a majority of its workforce. “We hoped this day would never come,” Convoy CEO Dan Lewis wrote in a memo sent to employees Thursday morning.

The startup sent shockwaves through the Seattle tech ecosystem and broader trucking sector after abruptly shutting down operations on Wednesday.

A wide-column store

 A wide-column store (or extensible record store) is a column-oriented DBMS and therefore a special type of NoSQL database.[1] It uses tables, rows, and columns, but unlike a relational database, the names and format of the columns can vary from row to row in the same table. A wide-column store can be interpreted as a two-dimensional key–value store.[1] Google's Bigtable is one of the prototypical examples of a wide-column store.[2]

Wide-column stores versus columnar databases[edit]

Wide-column stores such as Bigtable and Apache Cassandra are not column stores in the original sense of the term, since their two-level structures do not use a columnar data layout. In genuine column stores, a columnar data layout is adopted such that each column is stored separately on disk. Wide-column stores do often support the notion of column families that are stored separately. However, each such column family typically contains multiple columns that are used together, similar to traditional relational database tables. Within a given column family, all data is stored in a row-by-row fashion, such that the columns for a given row are stored together, rather than each column being stored separately.

Wide-column stores that support column families are also known as column family databases.[citation needed]

Notable examples[edit]

Notable wide-column stores [3] include:

加拿大献血

捐献血液在枫叶国是无偿、义务性的,国民自愿到血站(Canadian Blood Services,CBS)施捐,后者系非营利组织(前身为红十字会),在全国各地设有两万个采血点,永久与流动性的、运作时间固定或弹性,便利人来献血。 

加国的这一志愿性良举很盛行,许多人在大学毕业、考取驾照、觅就新职、生日、结婚、添丁等重要时节,都会选择捐血作为一种仪式以志庆贺。而在911事件、地震海啸、新冠瘟疫等劫难之际,又纷纷欲为国家社会做点贡献出把力、表示自己的拳拳爱心,最实际的行动就是径奔血站排队、撸起袖子“大出血”。

不过捐血这事儿也有规矩,并非想象中的一时性起说献就能献的,通常得经过一套比较繁杂严格的筛选程序,特别是首次去献者,为的是确保所奉的质量纯洁安全。

首先,详细登记个人有关资料,包括曾经去过哪些国家与地区,患过何种疾病及服药史;倘若1980年后在某些地域(像英、法等国)居住逾三个月,就不具捐献的资格,因要防止疯牛症的潜在传播。献者的年龄要满17岁,上不封顶,只要身体康健即可。还得回复一系列琐碎细致的问卷,列题约有60条之多,其中不少与性方面有关,要逐一如实作答,某些内容叫人脸红心跳、涉及个人隐私,也是为严格排除艾滋病以及肝炎、心脏病等。

其次,进行简单的体检,测量体温,体重须逾50公斤。查血色素要正常,然后才进入主题–采血环节,这约需时一刻钟,每次共抽500毫升。此过程中可看电视或手机、与血站雇员聊天;待一袋子血充满了,仪器自动停止,拔针下床;到休息区小憩,喝橙汁、吃小饼干等,补充一点液体与能量,同时观察有无“放血”后的不适反应等。

待确实无异常后,便可离开了。不日献者会收到邮寄来的捐血卡,告之一己的血型,下回来时出示该卡,经电脑核对,再重复上述的所有步骤,便可继续捐奉。每次献血总共费时约一个钟头,故来前要计划安排好相关日程。

同一献者的两次捐输之间,男性起码要隔上俩月,女性仨月,以便让机体充分休养生息,确保体能恢复如常。只要是体格健壮无恙,就可无限制的反复供献,毕竟成年人每次给出的血量,仅占全身血液总容积的1/10,不会影响整体健康状况。唯在失血量超过1/5时,才会出现血压下降、心跳加快等不良征象。故毋庸担忧捐献会导致贫血、虚脱等现象。

相反,经常性的献血可以刺激骨髓的造血机制生机勃勃,增加新陈代谢,益于身强力壮。许多老献血员辄以捐过的次数多而为荣、骄傲自豪,据报载加国最高龄的献血耆老95岁,是温哥华地区的一位女士,一共献了70年、170余次,总量达75升,真了不起,教人敬佩。而她也认定此乃其长寿的秘诀之一,义举利人益己。