Question

import math 

def BinarySearch( A , val , low , high ):
    if high < low :
        return -1 #not found 
    mid = low + (high - low ) /2 
    if A[mid] > val:
        return BinarySearch(A,val , low , high )
    if A[mid] < val :
        return BinarySearch(A,val,low,high)
    else: 
        return mid #found 


A = [ 12 , 23 , 2 , 33 , 123 , 4 , 5 , 2 , 54 , 555 , 21 ]
BinarySearch( A , 0 , 0, 10)

I tried to do Binary Search without using the bisect Module . But it gives an error such as this

 File "doubtrob.py", line 8, in BinarySearch
    return BinarySearch(A,val , low , high )
RuntimeError: maximum recursion depth exceeded

Answer 1

You are using exactly the same search space on each iteration. Also, you need to stop when high – low < 2, otherwise mid will eventually equal low, and you might still be stuck in an infinite loop.

As an aside, you can get mid more simply: (low + high)/2.