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…eds range (fixes trekhleb#2219) interpolationSearch could loop forever when the seek element was greater than sortedArray[rightIndex] while the range still contained values above it: valueDelta could exceed rangeDelta, producing a middleIndex beyond rightIndex, so rightIndex never changed and the loop repeated. Add the symmetric early-return check (seekElement > sortedArray[rightIndex]) mirroring the existing valueDelta < 0 check. This also guarantees the interpolated middleIndex stays inside [leftIndex, rightIndex], so every iteration shrinks the search range. Add regression tests for the reported input and similar cases.
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Description
interpolationSearchnever returns for some inputs where the seek element is missing:Trace: the first pass interpolates index 11 (
26 > 24) and setsrightIndex = 10. On the next pass the range is[2 ... 22], butvalueDelta(22) is larger thanrangeDelta(20), so the interpolated index isfloor(22 * 10 / 20) = 11, which is beyondrightIndex.sortedArray[11]is still> 24, sorightIndex = 11 - 1 = 10again, and the loop repeats forever.Fix: the function already returns
-1when the seek element is below the range (valueDelta < 0). This adds the symmetric check for a seek element above the range maximum (seekElement > sortedArray[rightIndex]), which also guaranteesvalueDelta <= rangeDelta, so the interpolated index always stays inside[leftIndex, rightIndex]and every iteration shrinks the range.Tests
should not loop forever when the seek element is above part of the rangecovers the reported input plus two similar missing-element cases. It hangs onmasterand passes with the fix.npm run lintclean.Fixes #2219