LC: Two Sum

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

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

You can return the answer in any order.

 

Example 1:

Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Output: Because nums[0] + nums[1] == 9, we return [0, 1].

Example 2:

Input: nums = [3,2,4], target = 6
Output: [1,2]

Example 3:

Input: nums = [3,3], target = 6
Output: [0,1]

 

Constraints:

  • 2 <= nums.length <= 105
  • -109 <= nums[i] <= 109
  • -109 <= target <= 109
  • Only one valid answer exists.
 
 
 
 1 class Solution:
 2   def twoSum(self, nums: List[int], target: int) -> List[int]:
 3     # number -> index
 4     map = {}
 5     for i, num in enumerate(nums):
 6       remain = target - num
 7       if remain in map:
 8         return [i, map[remain]]
 9       else:
10         map[num] = i
11         

 

  

知识点:

1 enumerate

2 hashmap

posted @ 2020-10-25 08:16  WingWing111  阅读(135)  评论(0编辑  收藏  举报