Hashmap LEFT JOIN

LEFT JOIN means all the values in the first hashmap are returned, and if values exist in the “right” hashmap, they are appended to the result row otherwise a null will be added in-pace.

Challenge

This challenge asks to implement a function that takes two hashmaps of a word and its synonym and a word with its antonym and should return a set of words with their synonym and antonym.

Approach & Efficiency

For my approach I looped over the first hashmap (left hashmap )that has words and their synonyms and add them to a list and add the antonym of that word if exists in the right hashmap. Then I add that arrayList to the answer arrayList of arrayLists , finally I return the answer. Complexity of my solution takes O(n)- n : the size of the left hashmap - for the space complexity and O(n*m)- n: the length of the left hashmap , m: complexity of getting a value for certain key - for time complexity.

Solution