LeetCode --> 771. Jewels and Stones

Jewels and Stones

You're given strings J representing the types of stones that are jewels, and S representing the stones you have.  Each character inS 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

 

代码

解法1：

class Solution {
public:
    int numJewelsInStones(string J, string S) {
        int nCount = 0;
        
        for(int i = 0; i < J.length(); i++) {
            for(int j = 0; j < S.length(); j++) {
                if(J[i] == S[j]) nCount++;
            }
        }
        
        return nCount;
    }
};

解法2：

class Solution {
public:
    int numJewelsInStones(string J, string S) {
        int res = 0;

        set<char> setJ(J.begin(), J.end());
        for (char s : S) if (setJ.count(s)) res++;

        return res;
    }
};

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