[Solved] Javascript Classwork 8-Recursion

Recursion

1. Write a recursive function to determine whether all digits of the number are odd or not.

Input		Output
4211133	false
7791	true
5	true

2. Given an array of numbers. Write a recursive function to find its minimal positive element. (if such element does not exist, return -1)․

Input			Output
[56, -9, 87, -23, 0, -105, 55, 1]	0
[45, -9, 15, 5, -78]	5
[-5, -9, -111, -1000, -7]	-1

3. Given an array of numbers which is almost sorted in ascending order. Find the index where sorting order is violated.

Input		Output
[2, 12, 15, 48, 64]	-1
[-9, -4, -4, 3, 12, 4, 5]	5

4. Given an array. Write a recursive function that removes the first element and returns the given array. (without using ​shift()​)

Input		Output
[6, 78, ‘n’, 0, 1]	[78, ‘n’, 0, 1]
[5]	[]
[]	[]

5. Given an array of nested arrays. Write a recursive function that flattens it. (Hint create function that concats arrays).

Input	Output
[1, [3, 4, [1, 2]], 10]	[1, 3, 4, 1, 2, 10]
[14, [1, [[[3, []]], 1], 0]	[14, 1, 3, 1, 0]

6. Given an array and a number N. ​ ​Write a recursive function that rotates an array N places to the left. (​Hint​: to add element to the beginning use ​unshift()​)

[‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’, ‘g’, ‘h’] 3	[‘d’, ‘e’, ‘f’, ‘g’, ‘h’, ‘a’, ‘b’, ‘c’]
[‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’, ‘g’, ‘h’] -2	[‘g’, ‘h’, ‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’]

7. Given a number. Write a function that calculates its sum of the digits and if that sum has more than 1 digit find the sum of digits of that number. Repeat that process if needed and return the result.

Input		Output
14	5
29	2
999999999999	9

8. Implement merge sort