Angorithm4 Webinar #9

Host By Jiawei Wang 2021-12-17

1.angorithm4.org Dev Process

Redesign a brand-new light index page, Hope you like it :)

index.png
  • Domain Register (USD 7.99/YR)
  • Web Server Basic (Apache httpd2, Ubuntu)
  • Server Language (php, C++)
  • Index Page Design (Custom CSS with Bootstrap)
  • Database (Sqlite)
  • Applications (Online Docker) (Chat Room)
  • User-friendly features (md -> html)
  • Personal Page, information, and other pages (Webinar, Projects…)
  • [ ]……..

Future Plan

Sources/m1.png Sources/m2.png Sources/m3.png Sources/m4.png

Minecraft in a Weekend

c.png

2. Hashing (Part II)

i. Revision: Buffer Pool

bufferpool

ii. Revision: Linear Probe Hashing (Static Hashing)

  • Static Assumption: You know the number of elements ahead of time.
  • Cost More Storiage but Faster (Handle Collision) Vs Cost Less Storiage but Slower(Wide Hash Function)
linear

If we hash into a slot and we find something that’s already there, I’m trying to insert something there.
We just keep scanning down to the next position and keep going until we find the first open slot

iii. Dynamic Hashing

  • The previous hash tables require the DBMS to know the number of elements it wants to store.

Otherwise it has rebuild the table if it needs to grow/shrink in size.

unordered_map?

Example

pageex
hash

1) Chained Hashing (Used in Java)

Maintain a linked list of buckets for each slot in the hash table.
Resolve collisions by placing all elements with the same hash key into the same bucket.

  • Similar to Linear Probe Hashing
chain

2) Extendible Hashing

“Only Split the chain when overflowed”

extendible

3) Linear Hashing

“Two Hash Functions”

Linearh