From 9791f1663cc501f5fe47531baa2e6a54eeead3fb Mon Sep 17 00:00:00 2001
From: Amal Bijoy <amalbijoy2007@gmail.com>
Date: Sun, 5 Apr 2026 22:27:11 +0530
Subject: [PATCH] Guard interpolation search denominator for equal endpoints

---
 Searching-algorithms/Interpolationsearch.java | 23 +++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/Searching-algorithms/Interpolationsearch.java b/Searching-algorithms/Interpolationsearch.java
index ed7bea1..44b738f 100644
--- a/Searching-algorithms/Interpolationsearch.java
+++ b/Searching-algorithms/Interpolationsearch.java
@@ -20,15 +20,20 @@ public static void main(String[] args) {
         } else {
             System.out.println("Element " + key + " was NOT Found in the entered Array.");
         }
-    }
-    public static int interpolationSearch(int arr[], int lo, int hi, int x) {
-        int pos;
-        if (lo <= hi && x >= arr[lo] && x <= arr[hi]) {
-            pos = lo + ((hi - lo) * (x - arr[lo])) / (arr[hi] - arr[lo]);
-            if (arr[pos] == x)
-                return pos;
-            if (arr[pos] < x)
-                return interpolationSearch(arr, pos + 1, hi, x);
+    }
+    public static int interpolationSearch(int arr[], int lo, int hi, int x) {
+        int pos;
+        if (lo <= hi && x >= arr[lo] && x <= arr[hi]) {
+            if (arr[lo] == arr[hi]) {
+                if (arr[lo] == x)
+                    return lo;
+                return -1;
+            }
+            pos = lo + ((hi - lo) * (x - arr[lo])) / (arr[hi] - arr[lo]);
+            if (arr[pos] == x)
+                return pos;
+            if (arr[pos] < x)
+                return interpolationSearch(arr, pos + 1, hi, x);
             if (arr[pos] > x)
                 return interpolationSearch(arr, lo, pos - 1, x);
         }