Guard interpolation search denominator when range endpoints are equal

[Nullkernel]

Motivation

• Prevent a divide-by-zero when computing the interpolation pos in interpolationSearch by handling the degenerate case where arr[lo] == arr[hi] before evaluating the formula.

Description

• Added an early if (arr[lo] == arr[hi]) branch inside interpolationSearch(int arr[], int lo, int hi, int x) that returns lo when that value equals x and returns -1 otherwise, and left the existing recursive interpolation flow unchanged for non-degenerate ranges.

Testing

• Attempted to compile with javac Searching-algorithms/Interpolationsearch.java, and compilation failed due to a pre-existing public-class/filename mismatch (DS_Interpolationsearch vs Interpolationsearch.java).

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Codex Task