题目如下

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

Example:

Given nums = [2, 7, 11, 15], target = 9,Because nums[0] + nums[1] = 2 + 7 = 9,return [0,1].

解题如下

class Solution:

    def twoSum(self, nums, target):

        """

        :type nums: List[int]

        :type target: int

        :rtype: List[int]

        """

        process={}      ###字典解题，先创建一个字典

        for i in range(len(nums)): ###用于循环查找数组

            if target - nums[i] in process:   ###如果目标值减去现在这个元素在字典process里面

                return [process[target-nums[i]],i]   ###就返回这个字典里process的index，以及nums元素的index

            process[nums[i]] = i  ### 如果目标值减去现在这个元素在字典process里面，就在字典里面添加这个当前元素的数值为key，index为数