The Runtime Theory
mediumLeetCode#binary-search#rotation

Search in Rotated Sorted Array

Find target in a strictly increasing array rotated at an unknown pivot, using logarithmic time.

The Runtime Theory Team25 min read
Solve it

Solving happens on the judge — come back and mark it done

Sample cases

innums=[4,5,6,7,0,1,2], target=0

out4

innums=[4,5,6,7,0,1,2], target=3

out-1

innums=[1], target=0

out-1

Find target in a strictly increasing array rotated at an unknown pivot, using logarithmic time.

A good solution should

  • State the invariant or decision rule that makes the approach correct.
  • Explain the time and space complexity in terms of the input sizes and required output.
  • Handle empty, minimal, duplicate, and boundary-shaped inputs covered by the contract.

Reasoning prompt

At least one half remains sorted. Identify which half contains the target before narrowing the interval.

Use the linked judge for the canonical problem. The examples above are compact TRT checks; write additional cases before submitting, especially for the boundary that tends to break your chosen invariant.

More practice in this topic

easy · binary searchBinary Searchmedium · binary searchFind First and Last Position of Elementmedium · binary searchFind Minimum in Rotated Sorted Array

One dispatch a week

The trace behind each problem, the tradeoff that explains it, and one technical dispatch per week — no noise.

One technical dispatch per week. No noise.

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