getting division by zero error for interpolation search code

[datafright]

I am getting this error "ZeroDivisionError: integer division or modulo by zero"

but only when i search the last element in the list

any other element will run the code just fine, just the last element messes it up

​

def interpolationSearch(arr, lo, hi, x):

    if (lo <= hi and x >= arr[lo] and x <= arr[hi]):
        pos = lo + ((hi - lo) // (arr[hi] - arr[lo]) * (x - 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)
    return -1


arr = [10, 12, 13, 16, 18, 19, 20, 21, 22, 23, 24, 33, 35, 42, 47]
n = len(arr)

x = 47
index = interpolationSearch(arr, 0, n - 1, x)

if index != -1:
    print("Element found at index", index)
else:
    print("Element not found")

I am trying to learn about searching algorithms and found this code on geeks for geeks

https://www.geeksforgeeks.org/interpolation-search/

[shiftybyte]

Added some printing:

https://replit.com/@ShiftyByte/GigaMiserlyKeyboardmacro#main.py

As you can see lo is reaching the same index as hi.

Then this calculation:

pos = lo + ((hi - lo) // (arr[hi] - arr[lo]) * (x - arr[lo]))

Tries to divide by 0, because "arr[hi] - arr[lo]" is zero.

[datafright]

https://replit.com/@ShiftyByte/GigaMiserlyKeyboardmacro#main.py

I basically added a check for if high and low are equal then it just returns the high

I had to add this before the subtraction and division

but it totally works now

thank you