Solutions to https://blog.svpino.com/2015/05/07/five-programming-problems-every-software-engineer-should-be-able-to-solve-in-less-than-1-hour

q1.py

test_list = [1,2,5,2]

def for_loop(the_list):
    result = 0

    for number in the_list:
        result += number

    return result

def while_loop(the_list):
    result = 0
    i = 0

    while i < len(the_list):
        result += the_list[i]
        i += 1

    return result

def recursion(the_list):
    try:
        head = the_list[0]
    except IndexError:
        return 0

    tail = the_list[1:]

    return head + recursion(tail)

print sum(test_list)
print for_loop(test_list)
print while_loop(test_list)
print recursion(test_list)

q2.py

def my_zip(list_1, list_2):
    i = 0

    result = []

    while i < len(list_1) and i < len(list_2):
        result.append(list_1[i])
        result.append(list_2[i])
        i += 1

    return result

print my_zip([1,2,3], ['a','b','c'])

q3.py

def fib():
    sequence = [0, 1]

    while len(sequence) < 100:
        sequence.append(sequence[-1] + sequence[-2])

    return sequence

import pprint

pprint.pprint(fib())

q4.py

import itertools

def max_combination(a_list):
    str_list = [str(el) for el in a_list]

    result = 0

    for permutation in itertools.permutations(str_list):
        str_number = ''.join(permutation)
        number = int(str_number)

        if result < number:
            result = number

    return result

print max_combination([50, 2, 1, 9, 98])

q5.py

operators = ['+', '-', '']

for op1 in operators:
    for op2 in operators:
        for op3 in operators:
            for op4 in operators:
                for op5 in operators:
                    for op6 in operators:
                        for op7 in operators:
                            for op8 in operators:
                                expression = (
                                    '1' + op1 +
                                    '2' + op2 +
                                    '3' + op3 +
                                    '4' + op4 +
                                    '5' + op5 +
                                    '6' + op6 +
                                    '7' + op7 +
                                    '8' + op8 +
                                    '9')

                                result = eval(expression)
                                if result == 100:
                                    print expression