EasyArraysFree practice
Two Sum
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01 · Problem
Given an array of integers nums and an integer target, return the 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.
02 · Examples
Example 01
Input
nums = [2,7,11,15], target = 9
Output
[0,1]
nums[0] + nums[1] = 2 + 7 = 9, so we return [0, 1].
Example 02
Input
nums = [3,2,4], target = 6
Output
[1,2]
nums[1] + nums[2] = 2 + 4 = 6, so we return [1, 2].
Example 03
Input
nums = [3,3], target = 6
Output
[0,1]
nums[0] + nums[1] = 3 + 3 = 6, so we return [0, 1].
03 · Constraints
- 012 <= nums.length <= 104
- 02-109 <= nums[i] <= 109
- 03-109 <= target <= 109
- 04Only one valid answer exists.
04 · Optimal complexity
- Time
- O(n)
- Space
- O(n)
05 · Two ways to work on it
Practice it alone or rehearse it as an interview.
Practice Mode gives you an editor and test runs, nothing else. AI Interview Mode puts a voice interviewer on the other side, adds a clock, and ends with a scored summary of the round.