More Binary search variants

# Search a sorted array of unknown length
# Degree of difficulty: Easy

Assume: Exception will be thrown for array out of bound.

Descriptive answer:
First find the length.
Then do a normal bin search.

How to find the length?
Assume, length 2^n.
Find out valid k for which no exception is thrown.

Again binsearch between 0 and 2^k+1. Consider exception in the
termination criteria.

# Search a sorted array of distinct integer for A[i]=i

# Degree of difficulty: Easy.



def binsearch_var3(list):

    l=0

    u=len(list)-1

    while l<=u:

        m=(l+u)/2

        print '%d %d' %(m,list[m])

        if list[m]==m:

            return m

        elif list[m]            l=m+1

        else:

            u=m-1



    return -1