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 arr.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 arr.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
