leetcode#33.py

def search(arr, l, h, key):
    if l > h:
        return -1

    mid = (l + h) // 2
    if arr[mid] == key:
        return mid

    # If arr[l...mid] is sorted
    if arr[l] <= arr[mid]:

        # As this subarray is sorted, we can quickly
        # check if key lies in half or other half
        if key >= arr[l] and key <= arr[mid]:
            return search(arr, l, mid - 1, key)
        return search(arr, mid + 1, h, key)

    # If arr[l..mid] is not sorted, then arr[mid... r]
    # must be sorted
    if key >= arr[mid] and key <= arr[h]:
        return search(arr, mid + 1, h, key)
    return search(arr, l, mid - 1, key)


# Driver program
arr = [12, 13, 14, 15, 16, 17, 18, 19, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]
key = 6
i = search(arr, 0, len(arr) - 1, key)
if i != -1:
    print("Index: %d" % i)
else:
    print("Key not found")