LeetCode167：Two Sum II - Input array is sorted

Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2.

Note:

• Your returned answers (both index1 and index2) are not zero-based.
• You may assume that each input would have exactly one solution and you may not use the same element twice.

Example:

Input: numbers = [2,7,11,15], target = 9
Output: [1,2]
Explanation: The sum of 2 and 7 is 9. Therefore index1 = 1, index2 = 2.

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LeetCode：链接

这题和剑指Offer_编程题42：和为s的两个数字是一个思路的。

class Solution(object):
    def twoSum(self, numbers, target):
        """
        :type numbers: List[int]
        :type target: int
        :rtype: List[int]
        """
        start = 0
        end = len(numbers) - 1
        while start < end:
            if numbers[start] + numbers[end] < target:
                start += 1
            elif numbers[start] + numbers[end] > target:
                end -= 1
            else:
                return [start+1, end+1]
        return []