all interview problems organized, and cleaned up repeats

Author: Mari Wahl

src/extra_interview_problems/math_arrays_and_strings/anagram.py

@@ -25,7 +25,24 @@ def is_anagram(s1, s2):
 
     return True
 
+''' verify if words are anagrams by comparing a sum of  Unicode code
+point of the character'''
 
+def get_unicode_sum(word):
+    s = 0
+    for p in word:
+        s += ord(p)
+    return s
+
+
+def is_anagram2(word1, word2):
+    '''
+    >>> is_anagram2('cat', 'tac')
+    True
+    >>> is_anagram2('cat', 'hat')
+    False
+    '''
+    return get_unicode_sum(word1) == get_unicode_sum(word2)
 
 
 if __name__ == '__main__':

src/extra_interview_problems/math_arrays_and_strings/anagrams_hash_table.txt

@@ -17,17 +17,17 @@
 It takes O(nlog n) times two.
 """
 
-def check_sum_hash_table(array, k):
+from collections import defaultdict, Counter
+
+def check_sum(array, k):
     '''
-    >>> check_sum_hash_table([3, 2, 6, 7, 9, 1], 8)
+    >>> check_sum([3, 2, 6, 7, 9, 1], 8)
     [(6, 2), (1, 7)]
-    >>> check_sum_hash_table([5, 2, 6, 7, 9, 1], 4)
+    >>> check_sum([5, 2, 6, 7, 9, 1], 4)
     []
     >>>
     '''
 
-    from collections import defaultdict
-
     dict = defaultdict()
     res = []
 
@@ -40,6 +40,32 @@ def check_sum_hash_table(array, k):
 
     return res
 
+
+def check_sum2(array, k):
+    '''
+    >>> check_sum2([1, 4, 2, 7, 1, 3, 10, 15, 3, 1], 6)
+    set([(3, 3)])
+    >>> check_sum2([1, 4, 2, 7, 1, 3, 10, 15, 3, 1], 0)
+    set([])
+    '''
+
+    dict = Counter()
+    res = set()
+
+    for i in array:
+        dict[i] += 1
+
+    for i in array:
+        if dict[k-i] > 0:
+            if i == k-i and dict[k-i] > 1:
+                    res.add((i, k-i))
+                    dict[k-i] -= 2
+            elif i == k-i:
+                res.add((i, k-i))
+                dict[k-i] -= 1
+
+    return res
+
 if __name__ == '__main__':
     import doctest
     doctest.testmod()

src/extra_interview_problems/math_arrays_and_strings/check_2_numbers_array_sum.py renamed to src/extra_interview_problems/math_arrays_and_strings/check_if_2_numbers_sum_to_k.py

@@ -5,12 +5,38 @@
 
 def fib_generator():
     a, b = 0, 1
+
     while True:
         yield b
         a, b = b, a+b
 
 
+def fib(n):
+    '''
+    >>> fib(2)
+    1
+    >>> fib(5)
+    5
+    >>> fib(7)
+    13
+    '''
+    if n < 3:
+        return 1
+
+    a, b = 0, 1
+    count = 1
+
+    while count < n:
+        count += 1
+        a, b = b, a+b
+
+    return b
+
+
 if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+
     fib = fib_generator()
     print(next(fib))
     print(next(fib))