What a skip list is
A skip list is a data structure that stores an ordered sequence of values and adds extra layers of links so that searches can skip over many values at once. It is built on top of an ordered linked list, but with additional forward connections arranged in levels. These extra links act like express lanes, letting a search move quickly toward the value it is looking for.
Layers of links
The idea behind a skip list is to have multiple levels of links. The lowest level connects every value in order, like an ordinary linked list. Higher levels connect only some of the values, skipping over others. These higher levels provide shortcuts, so a search can travel a long distance quickly before dropping down to lower levels for finer steps.
Searching quickly
To search a skip list, you start at the highest level and move forward along the shortcuts until you would overshoot the target, then drop down a level and continue. By repeatedly using the express lanes and then descending, the search skips over large portions of the list. This makes lookups much faster than scanning a plain ordered list one value at a time.
A simpler alternative to balanced trees
Skip lists offer efficient ordered search and updates similar to balanced trees, but many find them conceptually simpler. The layered-link approach achieves good performance without the restructuring rules that balanced trees use. This simplicity, combined with solid efficiency, is one reason skip lists are an appealing data structure for ordered collections.
Why skip lists matter
Skip lists matter because they provide a clever, relatively simple way to get fast search and update operations on ordered data. They are used in various systems as an alternative to balanced trees. Understanding the skip list clarifies how adding layers of shortcut links over an ordered list can dramatically speed up searching.
Why it matters
The skip list is a useful and elegant data structure. Understanding what it is - an ordered list with layered express-lane links for fast searching - clarifies an approachable way to achieve efficient ordered lookups. For anyone interested in computer science, it is a valuable concept to understand.
Related on Skillo
See also: What is a linked list? Explained, What is a binary search tree? Explained.
Sources
Published date reflects the original event date (2026-10-16). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.
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