Binary search coding solution

Binary search works on sorted array.

Worst complexity: O(log n)
Average complexity: O(log n)
Best complexity: O(1)
Space complexity: O(1)

Question:

Find the index of a given item

Solution

def binary_search(arr, item):
    left = 0
    right = len(arr) - 1

    while left <= right:
        mid = (left + right) // 2

        if item == arr[mid]:
            return mid
        elif item < arr[mid]:
            right = mid - 1
        elif item > arr[mid]:
            left = mid + 1

    return -1


arr = [10,20,30,40,50]
item = 50

result = binary_search(arr, item)
if result == -1:
    print('Item not found')
else:
    print(f'Item found at index {result}')