[算法学习][leetcode] 771 Jewels and Stones

https://leetcode.com/problems/jewels-and-stones/description/

题目

You’re 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

Note:

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

题目翻译

题目解析

参考答案

func numJewelsInStones(J string, S string) int {
    num := 0
    m := make(map[rune]int)

    for _, v := range J {
        m[v] = 1
    }

    for _, v := range S {
        if _, ok := m[v]; ok {
            num++
        }
    }

    return num
}