LeetCode 771. Jewels and Stones

You are given strings J representing the types of stones that are jewels, and S representing the stones you have. Each character in S is a type of stone you have. You want to know how many of the stones you have are also jewels.

The letters in J are guaranteed distinct, and all characters in J and S are letters. Letters are case sensitive, so “a” is considered a different type of stone from “A”.

Example 1:

Input: J = “aA”, S = “aAAbbbb”
Output: 3
Example 2:

Input: J = “z”, S = “ZZ”
Output: 0

S and J will consist of letters and have length at most 50.
The characters in J are distinct.

分析:将J中的所有字符在hash数组中标记为1,再遍历S,统计hash == 1的个数即为所求~


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