leetcode 1. Two Sum

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].

python代码

这个题就是利用字典，保存nums里面的数和其位置，然后用暴力枚举就完事了。

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        dic = {}
        length = len(nums)
        for i in range(length):
            dic[nums[i]] = i
        for i in range(length):
            res = target - nums[i]
            if res in dic.keys() and dic.get(res) != i:  #这个代码中dic.get(res)也可以用dic[res]代替
                return [i, dic.get(res)]