Overview
Rotated Array Search is a search method that uses ordering, indexing, predicates, or distance bounds to eliminate candidates. It is a good fit when the collection has enough structure to avoid checking every candidate.
CoreSource checked
Rotated Array Search
Rotated Array Search uses ordering or monotonic structure to eliminate candidates.
Quick Facts
Compact metadata for implementation and discovery.
- Category
- Searching
- Difficulty
- Intermediate
- Family
- Search
- Tier
- Core
- Status
- Verified
- Review
- Source Checked
- Sources
- 1
- Formulas
- 0
- Relationships
- 1
- Code example
- Ready
- Visualization
- Ready
Core Concepts
candidate pruningcomparison rulesearch intervalcandidate setquery comparisonelimination
Quick facts
Complexity
Runtime and memory behavior at a glance.
Best
O(1)
Average
O(log n)
Worst
O(n)
Space
O(1)
When to Use
- Use Rotated Array Search when the collection has the ordering, metric, or index structure it needs.
- Use it when setup or indexing cost is repaid by faster lookup.
When Not to Use
- Avoid when the data lacks the ordering, index, predicate, or metric structure the method needs.
- Avoid when setup costs exceed savings for a small one-off search.
What It Does
- Narrows candidate items
- Uses ordering, indexing, or distance tests
- Returns the best matching position or item
Use Cases
- Lookup in ordered data
- Nearest-neighbor search
- Predicate search
Inputs
- Collection or search space
- Target value or predicate
- Ordering or distance rule
Outputs
- Found item or position
- Nearest candidate
- Not-found result
Pseudocode
- 1.Initialize the candidate range, index, or frontier
- 2.Evaluate the target, predicate, or distance rule
- 3.Discard candidates that cannot improve the result
- 4.Repeat until the target or best candidate is found
- 5.Return the position, value, or not-found result
Canonical Example
- Input
- items = [1, 3, 5, 8], target or predicate = 5
- Output
- matching position or best candidate
- Explanation
- Rotated Array Search eliminates candidates until it finds the target or proves that no better candidate remains.
Implementation Notes
- Assert sorted, indexed, or metric preconditions where possible.
- Test empty, single-item, duplicate, and boundary target cases.
Common Pitfalls
- Using the method on unsorted or unindexed data silently breaks assumptions.
- Off-by-one bounds errors can skip valid candidates.
Interactive Mechanism Walkthrough
Indexed Interval & Boundary ProbeShow candidate regions shrinking as comparisons or distance tests eliminate options.
Target key: 41low=0, mid=4, high=9
4[0]
9[1]
15[2]
22[3]
27[4]
34[5]
41[6]
49[7]
58[8]
63[9]
Step 1 of 5: Initialize the candidate range, index, or frontier
searchNotes
Rotated Array Search operates in O(log n) time and O(1) space within the Search family. Often compared with Binary Search and Linear Search.
Sources (1)
What each reference supports for this entry.
Introduction to Algorithms (CLRS)
BookAlgorithms textbook support for binary-search invariants adapted to rotated sorted arrays.
Open sourceExplore Next
Good next jumps from the relationship graph, ranked for useful discovery.
Relationships
View full relationship pageSpecializesBinary Search
Rotated-array search specializes binary search by identifying which half of the rotated array remains sorted.
Related Algorithms
Tags
Search