Search Insert Position

Source

Given a sorted array and a target value, return the
index if the target is found. If not, return the 
index where it would be if it were inserted in order.

You may assume NO duplicates in the array.

Example
[1,3,5,6], 5 → 2

[1,3,5,6], 2 → 1

[1,3,5,6], 7 → 4

[1,3,5,6], 0 → 0

Challenge
O(log(n)) time

Python

class Solution:
    """
    @param A : a list of integers
    @param target : an integer to be inserted
    @return : an integer
    """
    def searchInsert(self, A, target):
        # write your code here
        if A is None or len(A)==0:
            return 0
        left=0
        right=len(A)-1

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

            if A[mid]==target:
                return mid
            elif A[mid]<target:
                left=mid+1
            else:
                right=mid-1
        return left