1. Two Sum (Leet Code) Python 풀이

 

1. 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]
Explanation: 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 <= 104
• -109 <= nums[i] <= 109
• -109 <= target <= 109
• Only one valid answer exists.

 

2. 풀이

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        left, right = 0, len(nums) - 1
        while left != right:
            if nums[left] + nums[right] < target:
                left = left + 1
            elif nums[left] + nums[right] > target:
                right = right - 1
            else:
                return [left, right]

 

3. 해설

투포인터

left = 처음

right = 마지막

left는 왼쪽부터 이동하고 right는 마지막부터 이동하며 자리 찾아내서 리턴