原题地址：https://oj.leetcode.com/problems/search-insert-position/

题意：

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

解题思路：二分查找的变种。注意最后一句是return left。

代码：

class Solution:
    # @param A, a list of integers
    # @param target, an integer to be inserted
    # @return integer
    def searchInsert(self, A, target):
        left = 0; right = len(A) - 1
        while left <= right:
            mid = ( left + right ) / 2
            if A[mid] < target:
                left = mid + 1
            elif A[mid] > target:
                right = mid - 1
            else:
                return mid
        return left