I tried "Five programming problems every Software Engineer should be able to solve in less than 1 hour" in Python.

exam1.py

#! /usr/bin/env python
# -*- coding:utf-8 -*-

num_list = range(10)

# use for roop
list_sum = 0
for num in num_list :
    list_sum += num
print 'list_sum counted with for roop           :', list_sum

# use while roop
list_sum, i = 0, 0
while i < len(num_list) :
    list_sum += num_list[i]
    i += 1
print 'list_sum counted with while roop         :', list_sum

# use recursive function
def count_sum (num_list, i=0) :
    if i == len(num_list) - 1 :
        return num_list[i]
    else :
        return num_list[i] + count_sum(num_list, i+1)
print 'list_sum counted with recursive function :', count_sum(num_list)

exam2.py

#! /usr/bin/env python
# -*- coding:utf-8 -*-

def combine_alternately (list1, list2) :
    new_list = []
    for e1, e2 in zip(list1, list2) :
        new_list += [e1, e2]
    return new_list

def combine_alternately2 (list1, list2) :
    new_list = []
    i, j = 0, 0
    while i < len(list1) or j < len(list2) :
        if i < len(list1) :
            new_list.append(list1[i])
        if j < len(list2) :
            new_list.append(list2[j])
        i += 1
        j += 1
    return new_list

if __name__ == '__main__' :
    list1, list2 = ['1', '2', '3', '4'], ['a', 'b', 'c']

    print combine_alternately(list1, list2)
    print combine_alternately2(list1, list2)

exam3.py

#! /usr/bin/env python
# -*- coding:utf-8 -*-

def fibonacci_series (size=100) :
    fibos = [0, 1]
    while len(fibos) < size :
        fibos.append(fibos[-1] + fibos[-2])
    return fibos

print fibonacci_series(size=100)

exam4.py

#! /usr/bin/env python
# -*- coding:utf-8 -*- 

import itertools

def max_num_combination (num_list) :
    max_num = 0
    for a_list in itertools.permutations(num_list, len(num_list)) :
        num = int(''.join(map(str, a_list)))
        if max_num < num :
            max_num = num
    return max_num

num_list = [50, 2, 1, 9]

print max_num_combination(num_list)

exam5.py

#! /usr/bin/env python
# -*- coding:utf-8 -*-

import itertools
from exam_2 import combine_alternately2

operations = ['+', '-', '']
for string in itertools.product(operations, repeat=8) :
    num_list = ['{0}'.format(i+1) for i in range(9)]
    formula = ''.join(combine_alternately2(num_list, string))
    if eval(formula) == 100 :
        print formula, '=', eval(formula)