algo

This is nothing useful but myself doing some algo exercises for practice since this is the kind of stuff asked in interviews but not necessarely used everyday in the field.

• List
• Stack
• Heap

• Tree

• Graph

  • Dijkstra

• Hash

• Sorts / Big O

  • Bubble sort -> On2 / On2 -> swap with neihboor again and again -> useless
  • Insertion sort -> On2 / On2 from 0 to n take lement and move to proper place in beginnging of sorted part
  • Selection sort -> On2 / On2. from o to n: find smallest element and move it to n
  • Quicksort -> OnLogn / On2. Pivot, create low, high lists, recurse and then merge back (low+pivot+high)
  • Merge sort -> Onlogn / Onlogn can parallel. Good for linked list, slow access ()
  • Heap sort -> OnLogn / OnLogn. Build heap and then traverse
  • Radix / Bucket sort -> Onk. Best for known & limited data ranges (ex: Ascii)
  • Introsort -> Quicksort / heapsort combo

• Search

  • Binary search

• Concurrency

  • Go mutex
  • Go routines / channels

• Design Patterns
  • Strategy -> Multiple implemtations behing interface decide which to use at runtime
  • Adater -> Basically a wrapper to adapt a model/API to another
  • Factory -> Create specific instances of an interface depending of params
  • Decorator -> Wrap model and "decorate" it with extra or modified features
  • Singleton -> Single instance
  • Iterator -> ... easy :)
  • Builder -> Construct object in several steps (add behavior). DSL's
  • Memento -> Typically do / undo ()~ stack