LeetCode | 771. Jewels and Stones

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题目

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.

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代码

class Solution {
    
    
public:
    int numJewelsInStones(string J, string S) {
    
    
        if(J.length() < 1 || S.length() < 1)
            return 0;
        set<char> jewels;
        int num = 0;
        for(int i = 0; i<J.length(); i++)
            jewels.insert(J[i]);
        for(int i = 0; i<S.length(); i++)
        {
    
    
            if(jewels.find(S[i]) != jewels.end())
                num++;
        }
        return num;
    }
};

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一次AC ^ _____________________________________ ^ 虽然效率令人堪忧