LeetCode - 771. Jewels and Stones

771. Jewels and Stones - easy

문제

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”.

제한사항

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

입출력 예

Example 1:

Input: J = "aA", S = "aAAbbbb"
Output: 3

Example 2:

Input: J = "z", S = "ZZ"
Output: 0

풀이

• Hash

func numJewelsInStones(J string, S string) int {
    result := 0
    m := make(map[rune]int)
    
    for _, v := range(J) {
        m[v]++
    }
    
    for _,v := range(S) {
        _, exist := m[v]
        if(exist) {
            result++
        }
    }
    
    return result
}