leetcode-771-Jewels-and-Stones

描述


You’re given strings J representing the types of stones that are jewels, and S representing the stones you have. Each character in Sis 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:

1
2
Input: J = "aA", S = "aAAbbbb"
Output: 3

Example 2:

1
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.

分析


J 作为一个集合,遍历 S,判断是否在 J 中,就像查询哈希列表一样,统计一下即可。

解决方案1(Java)


1
2
3
4
5
6
7
8
9
10
11
class Solution {
public int numJewelsInStones(String J, String S) {
int result = 0;
for (char c : S.toCharArray()) {
if (J.indexOf(c) != -1) {
result++;
}
}
return result;
}
}

题目来源