You are 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”.
Example 1:
Input: J = “aA”, S = “aAAbbbb”
Output: 3
Example 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.
题目大意：J是珠宝，S是自己拥有的石头，判断自己拥有的石头中有多少个珠宝～
分析：将J中的所有字符在hash数组中标记为1，再遍历S，统计hash == 1的个数即为所求～
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class Solution { public: int numJewelsInStones(string J, string S) { int ans = 0, hash[256] = {0}; for (auto i : J) hash[i] = 1; for (auto i : S) if (hash[i]) ans++; return ans; } }; |
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