Create 771-jewels_and_stones.py

Author: stevestar888

771-jewels_and_stones.py

@@ -0,0 +1,46 @@
+"""
+https://leetcode.com/problems/jewels-and-stones/
+
+"""
+class Solution(object):
+    
+    """
+    Strat: 
+        Make a set to store occurances for each jewel. Then, iterate through each stone
+        to see if it is a jewel.
+
+    Stats: O(J + S) time, O(J) space -- iterate thru J and S + set of size J to store Jewels
+        Runtime: 36 ms, faster than 6.54% of Python online submissions for Jewels and Stones.
+        Memory Usage: 12.7 MB, less than 76.19% of Python online submissions for Jewels and Stones.
+    """
+    def numJewelsInStones(self, J, S):
+        """
+        :type J: str
+        :type S: str
+        :rtype: int
+        """
+        jewels = set()
+        for jewel in J:
+            jewels.add(jewel)
+        
+        num_jewels = 0
+        for stone in S:
+            if stone in jewels:
+                num_jewels += 1
+        
+        return num_jewels
+    
+    """
+    (it is apparently faster if you actually do a brute force and not make a dictionary)
+    
+    Stats: O(J * S) time, O(1) space
+        Runtime: 20 ms, faster than 69.03% of Python online submissions for Jewels and Stones.
+        Memory Usage: 12.8 MB, less than 36.28% of Python online submissions for Jewels and Stones.
+    """
+    def numJewelsInStones(self, J, S):
+        """
+        :type J: str
+        :type S: str
+        :rtype: int
+        """
+        return sum([1 for s in S if s in list(J)])