jewels-and-stones.go

// You're given strings jewels representing the types of stones that are jewels, and stones representing the stones you have. Each character in stones is a type of stone you have. You want to know how many of the stones you have are also jewels.
//
// Letters are case sensitive, so "a" is considered a different type of stone from "A".
//
//  
// Example 1:
// Input: jewels = "aA", stones = "aAAbbbb"
// Output: 3
// Example 2:
// Input: jewels = "z", stones = "ZZ"
// Output: 0
//
//  
// Constraints:
//
//
// 	1 <= jewels.length, stones.length <= 50
// 	jewels and stones consist of only English letters.
// 	All the characters of jewels are unique.
//
//


func numJewelsInStones(J string, S string) int {
    m := make(map[rune]bool)
    for _, v := range J {
        m[v] = true
    }
    var c int
    for _, v := range S {
        if m[v] {
            c++
        }
    }
    return c
}