LeetCode2085. Count Common Words With One Occurrence

文章目录

• • 一、题目
  • 二、题解

一、题目

Given two string arrays words1 and words2, return the number of strings that appear exactly once in each of the two arrays.

Example 1:

Input: words1 = "leetcode","is","amazing","as","is", words2 = "amazing","leetcode","is"

Output: 2

Explanation:

• "leetcode" appears exactly once in each of the two arrays. We count this string.
• "amazing" appears exactly once in each of the two arrays. We count this string.
• "is" appears in each of the two arrays, but there are 2 occurrences of it in words1. We do not count this string.
• "as" appears once in words1, but does not appear in words2. We do not count this string.
  Thus, there are 2 strings that appear exactly once in each of the two arrays.
  Example 2:

Input: words1 = "b","bb","bbb", words2 = "a","aa","aaa"

Output: 0

Explanation: There are no strings that appear in each of the two arrays.

Example 3:

Input: words1 = "a","ab", words2 = "a","a","a","ab"

Output: 1

Explanation: The only string that appears exactly once in each of the two arrays is "ab".

Constraints:

1 <= words1.length, words2.length <= 1000

1 <= words1i.length, words2j.length <= 30

words1i and words2j consists only of lowercase English letters.

二、题解

class Solution {
public:
    int countWords(vector<string>& words1, vector<string>& words2) {
        unordered_map<string,int> map1;
        unordered_map<string,int> map2;
        for(auto w1:words1){
            map1[w1]++;
        }
        for(auto w2:words2){
            map2[w2]++;
        }
        int res = 0;
        for(auto w1:words1){
            if(map1[w1] == 1 && map2[w1] == 1) res++;
        }
        return res;
    }
};