Merge pull request #9419 from packy/master

Challenge 252 solutions by Packy Anderson

2 files changed, 102 insertions, 0 deletions

diff --git a/challenge-252/packy-anderson/python/ch-1.py b/challenge-252/packy-anderson/python/ch-1.py
new file mode 100755
index 0000000000..16a9fd6188
--- /dev/null
+++ b/challenge-252/packy-anderson/python/ch-1.py
@@ -0,0 +1,69 @@
+#!/usr/bin/env python
+
+def comma_join(arr):
+    return ', '.join(map(lambda i: str(i), arr))
+
+def specialElementIndices(n):
+    return list( filter(lambda x: n % x == 0, range(1, n+1)) )
+
+def english_list (strlist):
+    # given a list, join it in a way that makes sense
+    # to english speakers
+    last = strlist.pop(-1) # last element in array
+    if (len(strlist) == 0):
+        # using an array in a scalar context returns
+        # the number of elements in the array
+
+        # there was only one element in the list
+        return last
+
+    joined = ',\n'.join(strlist)
+    if (len(strlist) > 1):
+        # if there's more than element, add an Oxford comma
+        joined += ','
+
+    return f'{joined} and\n{last}'
+
+def specialNumberSquareSum(ints):
+    n = len(ints)
+
+    # find the list of indices for "special" numbers
+    specialIndices = specialElementIndices(n)
+    count = len(specialIndices)
+    explain_list = [
+        f"$ints[{x}] since {x} divides {n}"
+        for x in specialIndices
+    ]
+    explain = (
+        "There are exactly $count special elements " +
+        "in the given array:\n" + english_list(explain_list)
+    )
+
+    # find the special numbers themselves
+    special = [ ints[x - 1] for x in specialIndices ]
+
+    # find the sum of the squares
+    sumval = sum([ x ** 2 for x in special ])
+
+    explain += '\nHence, the sum of the squares of all special '
+    explain += 'elements of given array:\n'
+    explain += ' + '.join(map(lambda x: f'{x} * {x}', special))
+    explain += f' = {sumval}'
+
+    return (
+        sumval,
+        explain
+    )
+
+def solution(ints):
+    print(f'Input: @ints = ({comma_join(ints)})')
+    (sumval, explain) = specialNumberSquareSum(ints)
+    print(f'Output: {sumval}')
+    print('')
+    print(explain)
+
+print('Example 1:')
+solution([1, 2, 3, 4])
+
+print('\nExample 2:')
+solution([2, 7, 1, 19, 18, 3])
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diff --git a/challenge-252/packy-anderson/python/ch-2.py b/challenge-252/packy-anderson/python/ch-2.py
new file mode 100755
index 0000000000..b68a6502c2
--- /dev/null
+++ b/challenge-252/packy-anderson/python/ch-2.py
@@ -0,0 +1,33 @@
+#!/usr/bin/env python
+
+def uniqueSumZero(n):
+    zero_sum_list = []
+    x = 1
+    while n > 0:
+        if (n % 2 == 1): # n is odd
+            zero_sum_list.append(0)
+            n -= 1
+        else: # n is even
+            zero_sum_list.append(x * -1)
+            zero_sum_list.append(x)
+            x += 1
+            n -= 2
+    zero_sum_list.sort()
+    return zero_sum_list
+
+def comma_join(arr):
+    return ', '.join(map(lambda i: str(i), arr))
+
+def solution(n):
+    print(f'Input: $n = {n}')
+    zero_sum_list = uniqueSumZero(n)
+    print(f'Output: ({comma_join(zero_sum_list)})')
+
+print('Example 1:')
+solution(5)
+
+print('\nExample 2:')
+solution(3)
+
+print('\nExample 3:')
+solution(1)
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