# 19.4 Handling Collisions: Linear Probing and External Chaining In hashing, a collision occurs when we have multiple elements that have the same index in our array. {% embed url="" %} Professor Hug's Lecture on Collisions {% endembed %} There are two common methods to deal with collisions in hash tables: 1. **Linear Probing:** Store the colliding keys elsewhere in the array, potentially in the next open array space. This method can be seen with distributed hash tables, which you will see in later computer science courses that you may take. 2. **External Chaining:** A simpler solution is to store all the keys with the same hash value together in a collection of their own, such as a `LinkedList`. This collection of entries sharing a single index is called a **bucket**. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://cs61b-2.gitbook.io/cs61b-textbook/19.-hashing-i/19.4-handling-collisions-linear-probing-and-external-chaining.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.