4/17 Problems

Author: Alison Spittel

arrays/count_differences.py

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+"""
+Count the number of changes needed to make two words anagrams of one another.
+
+https://www.hackerrank.com/challenges/ctci-making-anagrams
+"""
+from collections import Counter
+
+def number_needed(a, b):
+	# O(N) Complexity
+    a_counter = Counter(a)
+    b_counter = Counter(b)
+    
+    differences = 0
+    
+    for l in a_counter:
+        if l in b_counter:
+            if a_counter[l] != b_counter[l]:
+                differences += abs(a_counter[l] - b_counter[l])
+        else:
+            differences += a_counter[l]
+            
+    for l in b_counter:
+        if l not in a_counter:
+            differences += b_counter[l]
+    
+    return differences

arrays/ransom_note.py

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+"""
+See if a word is available in the magazine to use for a ransom note.
+
+https://www.hackerrank.com/challenges/ctci-ransom-note
+"""
+from collections import Counter
+
+def ransom_note(magazine, ransom):
+    magazine_counter = Counter(magazine)
+    ransom_counter = Counter(ransom)
+    for word in ransom_counter:
+        if word not in magazine:
+            return False
+        elif ransom_counter[word] > magazine_counter[word]:
+            return False
+    return True