lc167. Two Sum II - Input array is sorted

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167. 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.

思路:[2,7,11,15]存为{2:0,7:1,11:2,15:3}的字典,遍历找到key相加等于target的两个,返回

代码 python3:

   def twoSum(self, numbers: List[int], target: int) -> List[int]:
        dic = {}
        for i, num in enumerate(numbers):
            if target-num in dic:
                return [dic[target-num]+1, i+1]
            dic[num] = i