Advent of Code 2020

Codes from Christmas coding event.

Useful functionalities:

• counting characters in a string - day 2, line 18

• Array.prototype.sum (sums an array) - day 9

• Array.prototype.min (gets maximum number of an array) - day 9

• Array.prototype.max (gets minimum number of an array) - day 9

• compareArrays (shallow comparison of arrays) - day 11

• String.prototype.setCharAt (changes one char in array) - day 11

• countCharInArray (counts character occurrences in an array) - day 11

• Array.prototype.countChar (same as before, but now as a prototype method) - day 20

• String.prototype.reverse (reversing a string) - day 20

• Array.prototype.rotateRight, Array.prototype.rotateLeft, Array.prototype.flip (rotating and flipping an array of strings) - day 20