From dafb096e656977f8c4b2c975c923337c475ba32e Mon Sep 17 00:00:00 2001
From: Jessica Kwok <jessicatckwok@gmail.com>
Date: Thu, 25 Mar 2021 14:38:13 -0700
Subject: [PATCH] Add solution using hash

---
 data_structures/arrays/jewels_and_stones.rb | 36 +++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/data_structures/arrays/jewels_and_stones.rb b/data_structures/arrays/jewels_and_stones.rb
index 881c7c5..a777534 100644
--- a/data_structures/arrays/jewels_and_stones.rb
+++ b/data_structures/arrays/jewels_and_stones.rb
@@ -44,6 +44,42 @@ def find_jewels(jewels, stones)
   result
 end
 
+puts find_jewels("aA", "aAAbbbb")
+# => 3
+puts find_jewels("z", "ZZ")
+# => 0
+
+#
+# Approach 2: Hash
+#
+# Time Complexity: O(n)
+#
+
+def find_jewels(jewels, stones)
+  jewels_array = jewels.split('')
+  stones_array = stones.split('')
+  result_hash = {}
+  result = 0
+
+  stones_array.each do |stone|
+    if result_hash[stone] 
+      result_hash[stone] += 1
+    else
+      result_hash[stone] = 1
+    end
+  end
+
+  jewels_array.each do |jewel|
+    if result_hash[jewel]
+      result += result_hash[jewel]
+    else
+      result
+    end
+  end
+
+  result
+end
+
 puts find_jewels("aA", "aAAbbbb")
 # => 3
 puts find_jewels("z", "ZZ")