Problem Description
Given two string arrays words1 and words2, return the number of strings that appear exactly once in each of the two arrays.
Key Insights
- We need to count the occurrences of each word in both arrays.
- Only words that appear exactly once in both arrays should be considered for the final count.
- Using hash tables (dictionaries) will help us efficiently track the counts of each word.
Space and Time Complexity
Time Complexity: O(n + m), where n is the length of words1 and m is the length of words2. We traverse both arrays to build the frequency counts and then compare the results.
Space Complexity: O(n + m) in the worst case, as we may store all unique words from both arrays.
Solution
To solve the problem, we will use two hash tables (dictionaries) to count the occurrences of each word in words1 and words2. After counting, we will iterate over one of the dictionaries and check if the words are present in the other dictionary with exactly one occurrence. This approach allows us to efficiently determine the common words that meet the criteria.