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.

Here are few examples.
[1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0

解題分析：

我們可以利用二分搜尋解決此類問題：

# -*- coding:utf-8 -*-
class Solution(object):
    def searchInsert(self, nums, target):
        left = 0
        right = len(nums) - 1
        while left <= right:
            mid = (left + right) / 2
            if nums[mid] < target:
                left = mid + 1
            elif nums[mid] > target:
                right = mid - 1
            else:
                return mid
        return left