data-structures-and-algorithms

401 data structures and algorithms code challenges

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Data Structures and Algorithms

Language: Python

Hashtable Left Join

Feature Tasks

Implement a simplified LEFT JOIN for 2 Hashmaps. Write a function that LEFT JOINs two hashmaps into a single data structure.

Method:

• Write a function called left join
• Arguments: two hash maps
  • The first parameter is a hashmap that has word strings as keys, and a synonym of the key as values.
  • The second parameter is a hashmap that has word strings as keys, and antonyms of the key as values.
• Return: The returned data structure that holds the results is up to you. It doesn’t need to exactly match the output below, so long as it achieves the LEFT JOIN logic

NOTES:

• Combine the key and corresponding values (if they exist) into a new data structure according to LEFT JOIN logic.
• 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.
• If no values exist in the right hashmap, then some flavor of NULL should be appended to the result row.

Whiteboard Process

Examples

Input

| Synonyms Hash Table | | | Antonyms Hash Table | | |—|—|—|—|—| | Key | Value | | Key | Value | | diligent | employed | | diligent | idle | | fond | enamored | | fond | averse | | guide | usher | | guide | follow | | flow | garb | | flow | jam | | wrath | anger | | wrath | delight |

Output

[
   ["font", "enamored", "averse"],
   ["wrath", "anger", "delight"],
   ["diligent", "employed", "idle"],
   ["outfit", "garb", NULL],
   ["guide", "usher","follow"]
]

Stretch Goal

Consider a RIGHT JOIN. Can you implement this as a new function? How about by passing an optional parameter to your initial function, to specify if LEFT JOIN or RIGHT JOIN logic should be used?

Approach & Efficiency