3Sum
MediumArraysTwo Pointers
Solve this the way you would in the interview: out loud, on a timer, with an AI interviewer asking follow-ups while you code. You get a scored report at the end.
Practice this as a mock interviewFree to start, no account neededProblem
Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.
Notice that the solution set must not contain duplicate triplets.
Examples
Input: nums = [-1,0,1,2,-1,-4]
Output: [[-1,-1,2],[-1,0,1]]
nums[0] + nums[1] + nums[2] = -1 + 0 + 1 = 0. nums[1] + nums[2] + nums[4] = 0 + 1 + (-1) = 0. The distinct triplets are [-1,0,1] and [-1,-1,2].
Input: nums = [0,1,1]
Output: []
The only possible triplet does not sum up to 0.
Input: nums = [0,0,0]
Output: [[0,0,0]]
The only possible triplet sums up to 0.
Constraints
- 3 <= nums.length <= 3000
- -10^5 <= nums[i] <= 10^5
What the interviewer grades
A correct solution is one of five scores. The report also grades problem understanding (did you clarify inputs and edge cases before coding), problem solving, communication while you work, code quality, and testing. See a sample report, or read up on the pattern in the lessons.