Join Joe Marini for an in-depth discussion in this video Hash tables, part of Programming Foundations: Algorithms.
- [Instructor] The last data structure…we'll examine is the hash table.…Some languages call these dictionaries,…but for the sake of consistency, I'll use…the term hash table in this course.…A hash table is a form of what's…called an associative array.…It's a data structure that maps keys…to their associated values, and it does this…using what's called a hash function.…This function uses the key to compute an index…into the slots that are in the hash table…and map the key to the value.…
Now, ideally, the hash function will assign…each key to a unique slot in the table…where the values are stored.…In reality, sometimes there are collisions…in which two separate keys each map…to the same slot in the table.…And in that case, the hash table has to have a way…of resolving those collisions so that…the correct value is mapped to the right key.…Now that's a bit of a complex subject,…so I'm not going to go into how hash functions work…and how collisions are resolved.…
Most languages and frameworks already have…hash table data structures that have…
Author
Released
11/8/2018- Measuring algorithm performance
- Working with data structures such as arrays, stacks, and queues
- Looping and recursion
- Sorting data
- Searching data
- Filtering and value counting with hash tables
Skill Level Beginner
Duration
Views
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Introduction
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What you should know1m 35s
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1. Overview
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What are algorithms?2m 44s
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2. Common Data Structures
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Arrays2m 29s
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Linked lists2m 36s
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Linked lists walkthrough7m 35s
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Stacks and queues2m 43s
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Hash tables7m 59s
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3. Recursion
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Understanding recursion3m 38s
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Simple recursion example3m 9s
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Power and factorial4m 14s
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4. Sorting Data
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Overview of sorting2m 4s
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The bubble sort5m 8s
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The merge sort2m 24s
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Implement the merge sort5m 10s
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The quicksort3m 31s
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Implement the quicksort5m 39s
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5. Searching Data
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Unordered list search3m 45s
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Ordered list search5m 30s
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6. Other Algorithms
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Find max value recursively3m 44s
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Conclusion
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Next steps1m 18s
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Video: Hash tables