adding improvements throughout and trees

Author: Alison Spittel

Diff for: arrays/equality_in_array.py

@@ -0,0 +1,12 @@
+"""
+What is the lowest number of deletions that someone can make to have an array with all of the same elements?
+
+From https://www.hackerrank.com/challenges/equality-in-a-array
+"""
+from collections import Counter
+
+def n_deletions(li):
+	c = Counter(li).most_common(1)[0][1]
+	return len(li) - c
+
+print(n_deletions([5, 5, 5, 3, 1]))

Diff for: recursion/possible_powers.py

@@ -0,0 +1,20 @@
+"""
+Finds the number of ways a number can be comprised of integers to the nth power. 
+
+From https://www.hackerrank.com/challenges/the-power-sum
+"""
+def possible_powers_sum(n, possible_powers):
+    if n == 0: return 1
+    if n < 0 or not possible_powers: return 0
+    return possible_powers_sum(n-possible_powers[0], possible_powers[1:]) + possible_powers_sum(n, possible_powers[1:])
+    
+    
+def powers(n, power):
+    return [n**power for n in range(1, int(n**(1/power)+1))]
+
+
+def possible_powers(n, power):
+    return possible_powers_sum(n, powers(n, power))
+
+
+print(possible_powers(10, 2))