2085 - Count Common Words With One Occurrence.

Easy

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 <= words1[i].length, words2[j].length <= 30

• words1[i] and words2[j] consists only of lowercase English letters.