The Runtime Theory
mediumLeetCode#binary-search-on-answer#monotonicity

Koko Eating Bananas

Find the minimum integer eating speed that finishes all piles within h hours, taking at most one pile per hour.

The Runtime Theory Team25 min read
Solve it

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

Sample cases

inpiles=[3,6,7,11], h=8

out4

inpiles=[30,11,23,4,20], h=5

out30

inpiles=[30,11,23,4,20], h=6

out23

Find the minimum integer eating speed that finishes all piles within h hours, taking at most one pile per hour.

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

Feasibility is monotonic in speed, so binary-search the answer. Compute per-pile ceiling division without floating point.

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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