JavaScript Algorithms

Snippets for a bunch of useful JavaScript algorithms.

Complexity - Beginner

naiveSearch()
Type	Loop in loop
How it works	Compares a string with another string and returns number of matches found.
Positive	Simple, good for small data sets.
Negative	Inefficient for large data sets.
Efficiency Average	O(n^2)

bubbleSort()
Type	Loop in loop
How it works	Swapping, sorting from smallest to largest.
Positive	Simple, good for small data sets.
Negative	Inefficient for large data sets.
Efficiency Average	O(n^2)

selectionSort()
Type	Loop in loop
How it works	Swapping, sorting from largest to smallest.
Positive	Simple, good for small data sets.
Negative	Inefficient for large data sets.
Efficiency Average	O(n^2)

insertionSort()
Type	Loop in loop
How it works	Sorting into new array.
Positive	Simple, good for small data sets and nearly sorted data, or when new data is addded continuously.
Negative	Inefficient for large data sets.
Efficiency Average	O(n^2)

Complexity - Intermediate

mergeSort()
Type	Recursive with loop
How it works	Splits arrays until each array has only one item (= is sorted). Then merge and sort each array until there's only one array left.
Positive	More complex, good for large data sets
Negative
Efficiency Average	O(n log n)

quickSort()
Type	Recursive with loop
How it works	Sets pivot on the mean value, puts smaller numbers left of pivot and larger right of pivot. Then sorts left half and right half of increasingly smaller sizes, until its done.
Positive
Negative	With too large data sets you might run out of call stacks.
Efficiency Average	O(n log n)

Complexity - Expert

radixSort()
Type	Loop in loop
How it works	Sorts an array of integers by loop-sorting them in buckets by number and then putting them back together.
Positive	Fast.
Negative	Only works on integers.
Efficiency Average	O(n k)