organizing 2014 interview problems

src/basic_examples/example_args.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+def simple2(a, *args):
+    print args
+
+def simple(*args):
+    print args
+
+def simple3(**kwargs):
+    print kwargs
+
+
+simple(1, 2, 3)
+simple2(1, 2, 3)
+simple3(x=1, y=2)

src/basic_examples/example_benchmark_decorator.py

@@ -1,5 +1,7 @@
 #!/usr/bin/env python
 
+__author__ = "bt3"
+
 
 import random
 

src/basic_examples/example_comp_lists.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+a = [3, 4, 5, 6, 7]
+
+
+# Filter elements greater than 4
+
+# Bad:
+
+b = []
+for i in a:
+    if i > 4:
+        b.append(i)
+print b
+
+# Good:
+print [i for i in a if i > 4]
+
+# Or:
+print filter(lambda x: x > 4, a)
+
+
+# Add three to all list members:
+
+# Bad
+b = []
+for i in range(len(a)):
+    b.append(a[i] + 3)
+print b
+
+# Good:
+print [i + 3 for i in a]
+
+# Or:
+print map(lambda i: i + 3, a)

src/basic_examples/example_decorators.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+
+def logger(func):
+    def inner(*args): #1
+        print "Arguments were: {0}".format(args)
+        return func(*args)
+    return inner
+
+@logger
+def foo(x, y):
+    return x+y
+
+print foo(1, 2)
+
+
+def sum(func):
+    s = 0
+    for i in func():
+        s += i
+    return s
+
+@sum
+def interate():
+    a = []
+    for i in range(10):
+        a.append(i)
+    return a
+
+print interate
+
+# which is the same as
+def interate():
+    a = []
+    for i in range(10):
+        a.append(i)
+    return a
+
+print sum(interate)

src/basic_examples/example_generator.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+def interate(x):
+    for i in range(x):
+        yield i
+
+def gen1():
+    a =  interate(10)
+    print a.next()
+    print a.next()
+    print a.next()
+
+
+def reverse(data):
+    for i in range(len(data)-1, -1, -1):
+        yield data[i]
+
+def gen2():
+    for c in reverse('awesome'):
+        print c
+
+if __name__ == '__main__':
+    gen1()
+    gen2()

src/basic_examples/example_lambda.py

@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+test = lambda x: x**2
+print test(3)

src/basic_examples/example_open_files.py

@@ -0,0 +1,10 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+filename = raw_input('Enter a file name: ')
+try:
+    f = open(filename, "r")
+except:
+    print 'There is no file named', filename
+

src/basic_examples/example_pickle.py

@@ -1,11 +1,33 @@
 #!/usr/bin/env python
 
+__author__ = "bt3"
 
 
-""" simple example of how to use pickle to export files """
-
 import pickle
 
+def import_pickle(filename):
+    fh = None
+    try:
+        fh = open(filename, "rb")
+        mydict2 = pickle.load(fh)
+        return mydict2
+
+    except (EnvironmentError) as err:
+        print ("{0}: import error: {0}".format(os.path.basename(sys.arg[0]), err))
+        return false
+
+    finally:
+        if fh is not None:
+            fh.close()
+
+
+def test_import_pickle():
+    pkl_file = 'test.dat'
+    mydict = import_pickle(pkl_file)
+    print(mydict)
+
+
+
 def export_pickle(data, filename='test.dat', compress=False):
 
     fh = None
@@ -33,3 +55,4 @@ def test_export_pickle():
 
 if __name__ == '__main__':
     test_export_pickle()
+    test_import_pickle()

src/basic_examples/example_queue.py

@@ -1,4 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 import Queue
 

src/basic_examples/example_string_format.py

@@ -1,3 +1,8 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
 foo = 'foo'
 bar = 'bar'
 

src/basic_examples/example_subprocess.py

@@ -0,0 +1,8 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+import subprocess,os
+
+os.system('ls')
+subprocess.call(['ls', '-1'], shell=True)

src/basic_examples/example_telnet.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 
-__author__ = "bt3gl"
+__author__ = "bt3"
 
 
 from telnetlib import Telnet

src/basic_examples/example_testing.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+
+def test_doctest():
+    '''
+    >>> 1 == 1
+    False
+    '''
+    pass
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+
+#####
+
+import unittest
+
+class BasicsTestCase(unittest.TestCase):
+
+    def test_find_name(self):
+        self.assertTrue(1 == 1)
+        self.assertFalse(1 == 2)
+
+if __name__ == '__main__':
+    unittest.main()
+
+
+
+#####
+
+# content of test_example.py, run with $ py.test
+#
+# run tests over the directory
+# $ nosetest
+
+
+def func(x):
+    return x + 1
+
+def test_answer():
+    assert func(3) == 4
+

src/extra_interview_problems/glassdoor/2014/abstract_strucutres/queue_with_stack.py

@@ -1,25 +1,27 @@
-class Queue():
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+class Queue(object):
     def __init__(self):
-        self.in_ = []
-        self.out = []
+        self.enq = []
+        self.deq = []
 
-    def enqueue(self, item):
-        self.in_.append(item)
+    def enqueue(self, value):
+        self.enq.append(value)
 
-    def deque(self):
-        if not self.out:
-            while self.in_:
-                self.out.append(self.in_.pop())
+    def dequeue(self):
+        if not self.deq:
+            while self.enq:
+                self.deq.append(self.enq.pop())
+        return self.deq.pop()
 
-        return self.out.pop()
+if __name__ == '__main__':
+    q = Queue()
 
-
-
-
-
-
-q = Queue()
-for i in range(10):
+    for i in range(1,10):
         q.enqueue(i)
-for i in range(10):
-    print(q.deque())
+
+    for i in range(1, 10):
+        print q.dequeue()

src/extra_interview_problems/glassdoor/2014/abstract_strucutres/stack_with_minumum.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+class Stack(object):
+    def __init__(self):
+        self.content = []
+        self.min_array = []
+        self.min = float('inf')
+
+    def push(self, value):
+        if value < self.min:
+            self.min = value
+
+        self.content.append(value)
+        self.min_array.append(self.min)
+
+    def pop(self):
+        if self.content:
+            value = self.content.pop()
+            self.min_array.pop()
+            if self.min_array:
+                self.min = self.min_array[-1]
+            return value
+        else:
+            return 'Empty List. '
+
+    def find_min(self):
+        if self.min_array:
+            return self.min_array[-1]
+        else:
+            return 'No min value for empty list.'
+
+
+
+if __name__ == '__main__':
+    q = Stack()
+
+    for i in range(15,20):
+        q.push(i)
+    for i in range(10,5,-1):
+        q.push(i)
+
+
+
+    for i in range(1, 13):
+        print q.pop(), q.find_min()

src/extra_interview_problems/glassdoor/2014/abstract_strucutres/stack_with_minumum.txt

@@ -1,9 +0,0 @@
-Another way:
-
-Store two stacks, one of which contains all of the items in the stack and one of which is a stack of minima.
-
-To push an element, push it onto the first stack. Check whether it is smaller than the top item on the second stack, if so, push it onto the second stack.
-
-To pop an item, pop it from the first stack. If it is the top element, simply return the element on the top of the second stack.
-
-O(1)...

src/extra_interview_problems/glassdoor/2014/advanced/lru_cache.py

@@ -1,4 +1,7 @@
-#!/bin/python3
+#!/usr/bin/env python3
+
+__author__ = "bt3"
+
 
 from functools import lru_cache
 

src/extra_interview_problems/glassdoor/2014/basic_examples/example_args.py

@@ -1,28 +0,0 @@
-#!/usr/bin/python
-
-def simple2(a, *args):
-    print args
-
-def simple(*args):
-    print args
-
-def simple3(**kwargs):
-    print kwargs
-
-
-simple(1, 2, 3)
-simple2(1, 2, 3)
-simple3(x=1, y=2)
-
-
-def logger(func):
-    def inner(*args): #1
-        print "Arguments were: {0}".format(args)
-        return func(*args)
-    return inner
-
-@logger
-def foo(x, y):
-    return x+y
-
-print foo(1, 2)

src/extra_interview_problems/glassdoor/2014/basic_examples/example_comp_lists.py

@@ -1,26 +0,0 @@
-Bad:
-
-# Filter elements greater than 4
-a = [3, 4, 5]
-b = []
-for i in a:
-    if i > 4:
-        b.append(i)
-Good:
-
-a = [3, 4, 5]
-b = [i for i in a if i > 4]
-# Or:
-b = filter(lambda x: x > 4, a)
-Bad:
-
-# Add three to all list members.
-a = [3, 4, 5]
-for i in range(len(a)):
-    a[i] += 3
-Good:
-
-a = [3, 4, 5]
-a = [i + 3 for i in a]
-# Or:
-a = map(lambda i: i + 3, a)

src/extra_interview_problems/glassdoor/2014/basic_examples/example_generator.py

@@ -1,13 +0,0 @@
-#!/usr/bin/env python
-
-__author__ = "bt3"
-
-" Example of generator."
-
-def reverse(data):
-    for i in range(len(data)-1, -1, -1):
-        yield data[i]
-
-if __name__ == '__main__':
-    for c in reverse('awesome'):
-        print c

src/extra_interview_problems/glassdoor/2014/basic_examples/example_lambda.py

@@ -1,4 +0,0 @@
-#!/usr/bin/env python
-
-teste = lambda x: x**2
-print teste(3)

src/extra_interview_problems/glassdoor/2014/basic_examples/example_testing.py

@@ -1,65 +0,0 @@
--------------------------------------------
-'''
->>> 1 == 1
-False
-'''
-
-if __name__ == '__main__':
-    import doctest
-    doctest.testmod()
-
--------------------------------------------
-
-import unittest
-
-class BasicsTestCase(unittest.TestCase):
-
-    def test_find_name(self):
-        self.assertTrue(1 == 1)
-        self.assertFalse(1 == 2)
-
-if __name__ == '__main__':
-    unittest.main()
-
--------------------------------------------
-
-# content of test_example.py, run with $ py.test
-
-def func(x):
-    return x + 1
-
-def test_answer():
-    assert func(3) == 4
-
--------------------------------------------
-
-# run tests over the directory
-$ nosetest
-
----------------------------------------------
-
-filename = raw_input('Enter a file name: ')
-try:
-    f = open(filename, "r")
-except:
-    print 'There is no file named', filename
-
-raise Exception('Invalid config file: expecting keys "aws_access_key", "aws_secret_key", "bucket"')
-g = lambda x: x ** 2
-
-try:
-    operation, filename = sys.argv[1:]
-except ValueError:
-    print __doc__
-    sys.exit(2)
-
-subprocess.call()
-try:
-    response = urllib2.urlopen()
-
------------------------------------------------
-
-import subprocess,os
-
-os.system('ls')
-subprocess.call(['ls', '-1'], shell=True)

src/extra_interview_problems/glassdoor/2014/basic_examples/import_pickle.py

@@ -1,36 +0,0 @@
-#!/usr/bin/env python
-
-
-__author__ = "Mari Wahl"
-__email__ = "marina.w4hl@gmail.com"
-
-
-""" an example of using pickle for importing data from files """
-
-
-import pickle
-
-def import_pickle(filename):
-    fh = None
-    try:
-        fh = open(filename, "rb")
-        mydict2 = pickle.load(fh)
-        return mydict2
-
-    except (EnvironmentError) as err:
-        print ("{0}: import error: {0}".format(os.path.basename(sys.arg[0]), err))
-        return false
-
-    finally:
-        if fh is not None:
-            fh.close()
-
-
-def test_import_pickle():
-    pkl_file = 'test.dat'
-    mydict = import_pickle(pkl_file)
-    print(mydict)
-
-
-if __name__ == '__main__':
-    test_import_pickle()

src/extra_interview_problems/glassdoor/2014/bitwise/clear_bits.py

@@ -1,4 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 ''' Clear a bit in a binary number.
     Like the reverse of set bit:

src/extra_interview_problems/glassdoor/2014/bitwise/find_bit_len.py

@@ -1,4 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 ''' Find how many bits a int has:
     1) Start with a mask of 1

src/extra_interview_problems/glassdoor/2014/bitwise/get_bit.py

@@ -1,4 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 ''' Get a bit in a binary number:
     1) Shifts 1 over by i bits

src/extra_interview_problems/glassdoor/2014/bitwise/num_bits_to_convert_2_nums.py

@@ -1,4 +1,7 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 ''' This method returns the number of bits that are necessary to change to convert two
     numbers A and B:

src/extra_interview_problems/glassdoor/2014/bitwise/set_bit.py

@@ -1,4 +1,9 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+
 ''' Set a bit in a binary number:
     1) Shifts 1 over by i bits
     2) make an OR with the number, only the value at bit i will change and all the others bit

src/extra_interview_problems/glassdoor/2014/bitwise/swap_in_place.py

@@ -1,4 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 '''
     swapping values in place without extra memory

src/extra_interview_problems/glassdoor/2014/bitwise/update_bit.py

@@ -1,4 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 ''' This method merges set bit and clean bit:
     1) first clear the bit at i using a mask such as 1110111

src/extra_interview_problems/glassdoor/2014/design/design_pattern.txt

@@ -1,21 +0,0 @@
-			 DESIGN PATTERNS
-                    ------------------------
-
-LISTENER/OBSERVER:
------------------
-
-- Example: a GUI as a listener to several objects. For any change in the state, it would update the display.
-
-
-SINGLETON PATTERN:
------------------
-
-- To make sure that there is exactly one instance of something in the program.
-
-
-MODEL-VIEW-CONTROLLER:
-----------------------
-
-- Design commonly used in user interfaces. The goal is to keep the data separate from the interface.
-- Separate programming entities to store the data (model), display the data (view) and modify the data (controlle).
-- The view usually makes heavy use of listeners to listen to changes and events in the model or controller.

src/extra_interview_problems/glassdoor/2014/design/design_text_editor.txt

@@ -1,8 +0,0 @@
-			DESIGN A TEXT EDITOR
-		-------------------------------------
-
-- Classes to set up the text editor: classes for the GUI, formatting, saving/loading files, handling input.
-
-- Use inheritance where it makes sense.
-
-- Use design patterns (such as MVC, listener, singleton).

src/extra_interview_problems/glassdoor/2014/design/example_decorator.py

@@ -1,39 +0,0 @@
-#!/usr/bin/python
-
-
-# testing generator
-
-def interate(x):
-    for i in range(x):
-        yield i
-
-a =  interate(10)
-
-print a.next()
-print a.next()
-print a.next()
-
-# testing decorator
-
-def sum(func):
-    s = 0
-    for i in func():
-        s += i
-    return s
-
-@sum
-def interate():
-    a = []
-    for i in range(10):
-        a.append(i)
-    return a
-
-print interate
-
-def interate():
-    a = []
-    for i in range(10):
-        a.append(i)
-    return a
-
-print sum(interate)

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/anagrams_hash_table.txt

@@ -1,3 +1,8 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
 Given an english word in the form of a string, how can you quickly find all valid anagrams for that string?
 
 First you go through each word in the dictionary, sort the letters of the word and use this as a key in a Hash Table. O(nln n).

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/balance.txt

@@ -1,3 +1,8 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
 This is the classic "you have 8 balls/coins, which are the same weight, except for one which is slightly heavier than the others. You also have an old-style balance. What is the fewest number of weighings to find the heavy coin/ball?
 
 Answer: 2! You need to use every information available:

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/check_2_numbers_array_sum.py

@@ -1,5 +1,6 @@
-#!/bin/python
+#!/usr/bin/env python
 
+__author__ = "bt3"
 
 """
 Given an integer x and an unsorted array of integers, describe an algorithm to

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/check_if_anagrams.py

@@ -1,4 +1,7 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 """ find whether two words are anagrams. Since sets do not count occurency, and sorting is O(nlogn)
 we will use hash tables. We scan the first string and add all the character occurences. Then we

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/check_palindrome.py

@@ -1,38 +0,0 @@
-#!/bin/python
-
-''' Check if palindrome'''
-
-
-def check_pal(string):
-    string = "".join(string.split(' '))
-    p1, p2 = 0, len(string)-1
-    pal = True
-    while p1 < p2:
-        if string[p1] != string[p2]:
-            pal = False
-            break
-        p1+=1
-        p2-=1
-    return pal
-
-
-def check_pal2(string):
-    string = "".join(string.split(' '))
-    if len(string)<2:
-        return True
-    if string[0] != string[-1]:
-        return False
-    return check_pal2(string[1:-1])
-
-
-if __name__ == '__main__':
-    string1 = "borrow or rob"
-    string2 = " draw ward"
-    string3 = "google is fun"
-    print(check_pal(string1))
-    print(check_pal(string2))
-    print(check_pal(string3))
-    print
-    print(check_pal2(string1))
-    print(check_pal2(string2))
-    print(check_pal2(string3))

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/combinations.py

@@ -1,16 +1,19 @@
-#!/usr/bin/python
-#
-''' give all the combinations of a str or list '''
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 
 def comb_str(l1):
+
     if len(l1) < 2:
         return l1
+
     result = []
     for i, c in enumerate(l1):
         result.append(c)
         for comb in comb_str(l1[i+1:]):
-            result.append(c + "".join(comb))
+            result.append(c + comb)
+
     return result
 
 

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/decide_if_permutation.py

@@ -1,22 +0,0 @@
-#!/usr/bin/env python
-
-def define_if_permutation(word1, word2):
-    """
-    >>> define_if_permutation('hello', 'lolhe')
-    True
-    >>> define_if_permutation('stripe', 'triipe')
-    False
-    """
-    if sorted(word1) == sorted(word2):
-        return True
-    else:
-        return False
-
-
-
-
-
-
-if __name__ == '__main__':
-    import doctest
-    doctest.testmod()

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/delete_duplicate_char_str.py

@@ -1,23 +1,36 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 '''  find and delete all the duplicate characters in a string '''
 
 
 import string
 
-def delete_unique_word(str1):
-    table_c = { key : 0  for key in string.ascii_lowercase}
-    for i in str1:
-        table_c[i] += 1
-    for key, value in table_c.items():
-        if value > 1:
-            str1 = str1.replace(key, "")
+from collections import Counter
+def delete_unique(str1):
+    '''
+    >>> delete_unique("Trust no one")
+    'on'
+    >>> delete_unique("Mulder?")
+    ''
+    '''
 
-    return str1
+    str_strip = ''.join(str1.split())
+    repeat = Counter()
+
+    for c in str_strip:
+        repeat[c] += 1
+
+    result = ''
+    for c, count in repeat.items():
+        if count > 1:
+            result += c
+
+    return result
 
 
 
 if __name__ == '__main__':
-    str1 = "google"
-    print delete_unique_word(str1) # == 'le'
-
+    import doctest
+    doctest.testmod()

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/fibonacci.py

@@ -1,9 +1,7 @@
 #!/usr/bin/env python
 
-
 __author__ = "bt3"
 
- ''' understanding generators'''
 
 def fib_generator():
     a, b = 0, 1

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/find_all_permutations_string.py

@@ -1,81 +0,0 @@
-#!/usr/bin/python
-
-
-def find_permutations(s):
-    if len(s) < 2: return s
-    res = []
-    for i, c in enumerate(s):
-        for perm in find_permutations(s[:i] + s[i+1:]):
-            res.append(c + "".join(perm))
-    return res
-
-
-def fpc(s):
-    return [s] if len(s)<2 else [c+p for i,c in enumerate(s) for p in fpc(s[:i]+s[i+1:])]
-
-
-def find_permutations_stdlib(s):
-    from itertools import permutations
-    return [''.join(p) for p in permutations(s)]
-
-
-def find_permutations2(s):
-    if len(s) < 2: return s
-    res = []
-    for i in range(len(s)):
-        for perm in find_permutations2(s[:i] + s[i+1:]):
-            res.append(s[i] + perm)
-    return res
-
-
-def verify_if_perm(s1, s2):
-    if len(s1) != len(s2): return False
-    s1 = sorted(s1)
-    s2 = sorted(s2)
-    return s1 == s2
-
-
-from collections import Counter
-def verify_if_perm2(s1, s2): # like anagram
-    if len(s1) != len(s2): return False
-    dict_aux = Counter()
-    for c in s1:
-        dict_aux[c] += 1
-    for c in s2:
-        dict_aux[c] -= 1
-    for item in dict_aux:
-        if dict_aux[item]:
-            return False
-    return True
-
-
-
-if __name__ == '__main__':
-    s1 = 'ufyfbufyfb'
-    s2 = 'buffybuffy'
-    s3 = 'uuyfbuuyfb'
-    s4 = ''
-
-    print(verify_if_perm(s1, s2))
-    print(verify_if_perm(s1, s3))
-    print(verify_if_perm(s1, s4))
-    print
-    print(verify_if_perm2(s1, s2))
-    print(verify_if_perm2(s1, s3))
-    print(verify_if_perm2(s1, s4))
-
-    print
-
-    s = 'hat'
-    print find_permutations(s)
-    print fpc(s)
-    print find_permutations_stdlib(s)
-    print find_permutations2(s)
-    print
-    print find_permutations(s4)
-    print fpc(s4)
-    print find_permutations_stdlib(s4)
-    print find_permutations2(s4)
-
-
-

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/find_if_is_substr.py

@@ -1,4 +1,7 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 def isSubstr(s1, s2):
     if s1 in s2 or s2 in s1: return True

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/find_if_unique_char.py

@@ -1,5 +1,9 @@
 #!/usr/bin/env python
 
+__author__ = "bt3"
+
+
+
 import collections
 
 def find_if_unique_chars(word):
@@ -13,11 +17,13 @@ def find_if_unique_chars(word):
     unique = True
 
     counter = collections.Counter()
+
     for c in word:
         if not counter[c]:
             counter[c] += 1
         else:
             unique = False
+
     return unique
 
 

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/find_largest_sum.py

@@ -1,4 +1,8 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
 
 '''You are given an array of integers (both positive and negative). Find the contiguous
 sequence with the largest sum. Return the sum.'''

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/find_non_repeating_number.py

@@ -1,4 +1,7 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 from collections import defaultdict
 

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/find_sum_ints.py

@@ -1,7 +1,8 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
-'''Design an algorithm to find all pairs of integers within an array
-    which sum to a specified value.'''
 
 from collections import defaultdict
 

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/finding_gcd.py

@@ -1,4 +1,7 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 
 def finding_gcd(a, b):

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/finding_if_prime.py

@@ -1,6 +1,8 @@
-#!/usr/bin/python3
-# mari von steinkirch @2013
-# steinkirch at gmail
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
 
 import math
 import random

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/generate_prime.py

@@ -1,6 +1,7 @@
-#!/usr/bin/python3
-# mari von steinkirch @2013
-# steinkirch at gmail
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 import math
 import random

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/get_float_rep_bin.py

@@ -1,4 +1,7 @@
-#!/usr/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 ''' Given a real number between 0 and 1 (eg: 0.72), this method print the binary
     representation. If the Number cannot be represented accurately in binary, with at

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/interserction_two_arrays.py

@@ -1,7 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 
-__author__ = "Mari Wahl"
-__email__ = "marina.w4hl@gmail.com"
+__author__ = "bt3"
 
 
 

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/max_subarray_stocks.py

@@ -1,3 +1,9 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+
 def beating_stock(array):
 
     imin = 0

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/number_of_zeros_factorial.txt

@@ -1,3 +1,9 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+
 How to know how many 0 are in 100!
 
 You look for the primes that multiply to 10, i.e. 2 and 5.

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/permutations.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+
+def perm(str1):
+    '''
+    >>> perm('123')
+    ['123', '132', '231', '213', '312', '321']
+    '''
+
+    if len(str1) < 2:
+        return str1
+
+    res = []
+    for i, c in enumerate(str1):
+        for cc in perm(str1[i+1:] + str1[:i]):
+            res.append(c + cc)
+    return res
+
+
+def perm2(str1):
+    '''
+    >>> perm2('123')
+    ['123', '132', '213', '231', '312', '321']
+    '''
+    from itertools import permutations
+    return [''.join(p) for p in permutations(str1)]
+
+
+def ispermutation(s1, s2):
+    '''
+    >>> ispermutation('231', '123')
+    True
+    >>> ispermutation('231', '153')
+    False
+    '''
+
+    from collections import Counter
+    aux = Counter()
+    for i in s1:
+        aux[i] += 1
+    for i in s2:
+        aux[i] -= 1
+    for v in aux.values():
+        if v != 0:
+            return False
+    return True
+
+
+
+
+def ispermutation2(s1, s2):
+    '''
+    >>> ispermutation2('231', '123')
+    True
+    >>> ispermutation2('231', '153')
+    False
+    '''
+    if sorted(s1) == sorted(s2):
+        return True
+    else:
+        return False
+
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/ransom_note.py

@@ -1,3 +1,9 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
+
 from collections import Counter
 
 def check_if_ransom_note(magazines, note):

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/rev_string.py

@@ -1,4 +1,8 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+
 
 ''' Reverting a string '''
 

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/reverse_words.py

@@ -1,5 +1,9 @@
 #!/usr/bin/env python
 
+__author__ = "bt3"
+
+
+
 def invert_word(word):
     """
     >>> invert_word('stripe is awesome')

src/extra_interview_problems/glassdoor/2014/math_arrays_and_strings/reverse_words_sentence.py

@@ -1,5 +1,6 @@
-#!/usr/bin python
+#!/usr/bin/env python
 
+__author__ = "bt3"
 
 
 def reversing_words_setence_py(s):

src/extra_interview_problems/glassdoor/2014/sorting_and_searching/deck_shuffling.txt

@@ -1,3 +0,0 @@
-How to shuffle an array or a deck of cards so each shuffle has the same probability?
-
-go thru the array shuffling each element with any random element after that.

src/extra_interview_problems/glassdoor/2014/sorting_and_searching/quick_sort.py

@@ -1,17 +1,27 @@
-#!/bin/python
+#!/usr/bin/env python
 
-''' Quick sort an array '''
+__author__ = "bt3"
 
 
-def quick_sort(arr):
-    if len(arr) < 2: return arr
-    piv = len(arr)//2
-    left = [x for i, x in enumerate(arr) if x <= arr[piv] and i != piv]
-    right = [x for i, x in enumerate(arr) if x > arr[piv] and i != piv]
-    return quick_sort(left) + [arr[piv]] + quick_sort(right)
+def qs(array):
+    '''
+    >>> qs([4,1,6,2,7,9,3])
+    [1, 2, 3, 4, 6, 7, 9]
+    '''
+    if len(array) < 2:
+        return array
 
+    piv = len(array)//2
+    piv_element = array[piv]
+    new_array = array[:piv] + array[piv+1:]
+
+    left  = [a for a in new_array if a <= piv_element]
+    right = [a for a in new_array if a > piv_element]
+
+
+    return qs(left) + [array[piv]] + qs(right)
 
 
 if __name__ == '__main__':
-    arr = [8, 5, 2, 6, 1, 2, 9, 4]
-    print(quick_sort(arr))
+    import doctest
+    doctest.testmod()

src/extra_interview_problems/glassdoor/2015/alpha_permutation.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 ''' Write code to generate all possible case permutations of a given
 lower-cased string

src/extra_interview_problems/glassdoor/2015/anagram.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 from collections import Counter
 

src/extra_interview_problems/glassdoor/2015/binary_search.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 
 def binary_search_rec(array, item, lo=0, hi = None):

src/extra_interview_problems/glassdoor/2015/check_if_3_numbers_sum_to_zero.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 ''' Determine if an Array of integers contains 3 numbers that sum to 0 '''
 

src/extra_interview_problems/glassdoor/2015/check_if_bst.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 Given a tree find out whether is a BST or not

src/extra_interview_problems/glassdoor/2015/check_if_palindrome.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 
 from collections import defaultdict

src/extra_interview_problems/glassdoor/2015/check_non_overlapping_intervals.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 given an array of intervals, return max number of non-overlapping intervals

src/extra_interview_problems/glassdoor/2015/find_if_numbers_sum_to_k.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 Given an unsorted array of numbers (that may contain repeated numbers),

src/extra_interview_problems/glassdoor/2015/find_longest_str_unique_chars.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 given a string, find longest string with unique characters

src/extra_interview_problems/glassdoor/2015/find_nth_fibonacci.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 Write a function to find the nth Fibonacci number.

src/extra_interview_problems/glassdoor/2015/find_prime_factors.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 find prime factors of a number.

src/extra_interview_problems/glassdoor/2015/longest_common_prefix.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 Given two strings, write a function
@@ -32,6 +35,15 @@ def lcp(s1, s2):
 
     return len(lcp)
 
+def lcppy(x):
+    '''
+    >>> lcppy([[3,2,1], [3,2,1,4,5]])
+    [3, 2, 1]
+    '''
+
+    import os
+    return os.path.commonprefix(x)
+
 if __name__ == '__main__':
     import doctest
     doctest.testmod()

src/extra_interview_problems/glassdoor/2015/merge_and_sort_two_arrays.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 You have two arrays with N integers in them. Merge those arrays using a

src/extra_interview_problems/glassdoor/2015/permutations.py

@@ -1,4 +1,6 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 ''' Generate all permutations of an alphanumeric string '''
 

src/extra_interview_problems/glassdoor/2015/sum_two_numbers_as_strings.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 find the sum of two integers represented as strings,

src/extra_interview_problems/glassdoor/2015/transversing_bt.py

@@ -1,4 +1,6 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
 
 '''
 Reconstruct a binary tree given two sequences of node traversals,

src/extra_interview_problems/glassdoor/2015/trie.py

@@ -1,4 +1,7 @@
-#!/bin/python
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
 
 '''
 Implement a trie. (Write the API and code for inserting into a trie).