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Tested Python solution for LeetCode 1 with 15 pytest cases. Generate a practice environment with lcpy.
lcpy gen -n 1 # by problem number
lcpy gen -s two_sum # by problem name
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.
Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Input: nums = [3,2,4], target = 6
Output: [1,2]
Input: nums = [3,3], target = 6
Output: [0,1]
class Solution:
# Time: O(n)
# Space: O(n)
def two_sum(self, nums: list[int], target: int) -> list[int]:
seen: dict[int, int] = {}
answers: list[list[int]] = []
for i, num in enumerate(nums):
complement = target - num
if complement in seen:
answer = [seen[complement], i]
answers.append(answer)
seen[num] = i
if len(answers) > 1:
raise ValueError(f"Found {len(answers)} answers in the solution: {answers}")
return answers[0] if answers else []
| Time | Space |
|---|---|
| O(n) | O(n) |