Hashmap
Hashmaps are always a good datatype to consider using when writing algorithms because of its time complexity.
Related
Graphs: https://medium.com/swlh/data-structures-graphs-50a8a032db03
Linked Lists: https://medium.com/@mariam.jaludi/data-structures-linked-lists-8f277b61cca
Trees: https://medium.com/@mariam.jaludi/data-structures-trees-1bafa942cd60
Stacks and Queues: https://medium.com/swlh/stacks-and-queues-f281aa5462cf
Heaps: https://medium.com/swlh/data-structures-heaps-b039868a521b
References
https://medium.com/@mariam.jaludi/i-need-to-understand-hashmaps-3ab690c1828e