USE RUBY PROGRAMMING LANGUAGE FOR THE SOLUTION
Problem 1

Where a is an array, a.delete(obj) deletes every item from a that is equal to obj:

>> a

=> [1, 2, 1, 3, 1, 4, 2, 5]

>> a.delete(1)

=> 1

>> a

=> [2, 3, 4, 2, 5]

Write the function delete_first(a, obj) that deletes from a only its first item that is equal to obj, if any. The function returns the modified array.

>> a

=> [1, 2, 1, 3, 1, 4, 2, 5]

>> delete_first(a, 1)

=> [2, 1, 3, 1, 4, 2, 5]

>> a

=> [2, 1, 3, 1, 4, 2, 5]

>> delete_first(a, 1)

=> [2, 3, 1, 4, 2, 5]

>> a

=> [2, 3, 1, 4, 2, 5]

>> delete_first(a, 18)

=> [2, 3, 1, 4, 2, 5]

>> a

=> [2, 3, 1, 4, 2, 5]

 

Problem 2

The Fibonacci sequence fib is defined thus: fib(1) = fib(2) = 1, and fib(n) = fib(n-1)+fib(n-2) for n>2. Write a function fib_array(n) that returns an array containing the first n values of the Fibonacci sequence. For example:

print fib_array(1)	# [1]
print fib_array(2)	# [1, 1]
print fib_array(10)	# [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]

 

Problem 3

 

Write a function fib(n) that returns the n’th Fibonacci value:

print fib(10)	# 55
print fib(100)	# 354224848179261915075