Description

1. Sum First Last
Write a function that calculates and prints the sum of the first and the last elements in an array.
The input comes as array of string elements holding numbers.
The output is the return value of your function.
Example
Input Output Input Output
[’20’, ’30’, ’40’] 60 [‘5′, ’10’] 15
2. Even Position Element
Write a function that finds the elements at even positions in an array.
The input comes as array of string elements.
The output is the return value of your function. Collect all elements in a string, separated by space.
Examples
Input Output Input Output
[’20’, ’30’, ’40’] 20 40 [‘5′, ’10’] 5
3. Negative / Positive Numbers
Write a JS function that processes the elements in an array one by one and produces a new array. Prepend each negative element at the front of the result and append each positive (or 0) element at the end of the result.
The input comes as array of number elements.
The output is printed on the console, each element on a new line.
Example
Input Output Input Output
[7, -2, 8, 9] -2
7
8
9 [3, -2, 0, -1] -1
-2
3
0
4. Last K Numbers Sequence
You are given two integers n and k. Write a JS function that generates and prints the following sequence:
• The first element is 1
• Every following element equals the sum of the previous k elements
• The length of the sequence is n elements
The input comes as two number arguments. The first element represents the number n, and the second – the number k.
The output is printed on the console on a single line, separated by space.
Example
Input Output Input Output
6, 3 1 1 2 4 7 13 8, 2 1 1 2 3 5 8 13 21
Explanation
The 2nd element (1) is the sum of the 3 elements before it, but there is only 1, so we take that. The third element is the sum of the first 2 (1 and 1) and the 4th – the sum of 1, 1 and 2. The 5th element is the sum of the 2nd, 3rd and 4th (1, 2 and 4) and so on.
5. Process Odd Numbers
You are given an array of numbers. Write a JS function that prints the elements at odd positions from the array, doubled and in reverse order.
The input comes as array of number elements.
The output is printed on the console on a single line, separated by space.
Example
Input Output Input Output
[10, 15, 20, 25] 50 30 [3, 0, 10, 4, 7, 3] 6 8 0
6. Smallest Two Numbers
Write a function that prints the two smallest elements from an array of numbers.
The input comes as array of number elements.
The output is printed on the console on a single line, separated by space.
Example
Input Output Input Output
[30, 15, 50, 5] 5 15 [3, 0, 10, 4, 7, 3] 0 3
7. Biggest Element
Write a function that finds the biggest element inside a matrix.
The input comes as array of arrays, containing number elements (2D matrix of numbers).
The output is the return value of your function. Find the biggest element and return it.
Examples
Input Output Input Output
[[20, 50, 10],
[8, 33, 145]] 145 [[3, 5, 7, 12],
[-1, 4, 33,
2],
[8, 3, 0, 4]] 33
8. Diagonal Sums
A square matrix of numbers comes as an array of strings, each string holding numbers (space separated). Write a function that finds the sum at the main and at the secondary diagonals.
The input comes as array of arrays, containing number elements (2D matrix of numbers).
The output is printed on the console, on a single line separated by space. First print the sum at the main diagonal, then the sum at the secondary diagonal.
Example
Input Output Input Output
[[20, 40],
[10, 60]] 80 50 [[3, 5, 17],
[-1, 7, 14],
[1, -8, 89]] 99 25
9. Equal Neighbors
Write a function that finds the number of equal neighbor pairs inside a matrix of variable size and type (numbers or strings).
The input comes as array of arrays, containing string elements (2D matrix of strings).
The output is return value of you function. Save the number of equal pairs you find and return it.
Example
Input Output Input Output
[[‘2’, ‘3’, ‘4’, ‘7’, ‘0’],
[‘4’, ‘0’, ‘5’, ‘3’,
‘4’],
[‘2’, ‘3’, ‘5’, ‘4’,
‘2’],
[‘9’, ‘8’, ‘7’, ‘5’,
‘4’]] 1 [[‘test’, ‘yes’, ‘yo’,
‘ho’],
[‘well’, ‘done’, ‘yo’,
‘6’],
[‘not’, ‘done’, ‘yet’,
‘5’]] 2