FresherFresher (0–1 yrs)CodingPythonGoogleAmazonMetaMicrosoftApple
Two Sum
Given an array of integers nums and an integer target, return indices of the two numbers that add up to target. Assume exactly one solution.
Answers use simple, clear English.
Audio N/ATime: O(n)Space: O(n)
Quick interview answer
Use a hash map from value → index. For each number x, check if target - x exists in the map. One pass, O(n) time, O(n) space.
Detailed answer
Use a hash map from value → index. For each number x, check if target - x exists in the map. One pass, O(n) time, O(n) space.
Code example
def two_sum(nums: list[int], target: int) -> list[int]:
seen: dict[int, int] = {}
for i, x in enumerate(nums):
need = target - x
if need in seen:
return [seen[need], i]
seen[x] = i
return []Practice code · python (view only · no execution)
def two_sum(nums: list[int], target: int) -> list[int]:
seen: dict[int, int] = {}
for i, x in enumerate(nums):
need = target - x
if need in seen:
return [seen[need], i]
seen[x] = i
return []fresherjuniormid#array#hashmap#blind75