Two|Two Sum II - Input array is sorted

1.传统做法是两个指针同时移动,这样的话时间复杂度是o(n)

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

【Two|Two Sum II - Input array is sorted】2.用字典记录下每个number 边记录边判断
···
class Solution(object):
def twoSum(self, numbers, target):
"""
:type numbers: List[int]
:type target: int
:rtype: List[int]
"""
dic = {}
for i,num in enumerate(numbers):
if (target - num) in dic:
return [dic[target - num], i+1]
else:
dic[num] = i+1
···

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