思路：

數列滿足遞增，設兩個頭尾兩個指標low和high，

若array[low]+array[high]==tsum，就是答案（low和high相差越遠乘積越小）

若array[low]+array[high]>tsum，high-=1

若array[low]+array[high]>tsum，low+= 1

# -*- coding:utf-8 -*-
class Solution:
    def FindNumbersWithSum(self, array, tsum):
        # write code here
        low=0
        high=len(array)-1
        res=[]
        while low<high:
            if array[low]+array[high]==tsum:
                res.append(array[low])
                res.append(array[high])
                low+=1
                high-=1
            elif array[low]+array[high]>tsum:
                high-=1
            else:
                low+=1
        return res[:2]