Your free access ends in 7 days — and you haven’t tried it yet. Watch one algorithm run, start to finish. It takes about two minutes.

Try one problem
0
Problem

3Sum

LeetCode #15Medium
Find all unique triplets that sum to zero

Given an integer array, find all unique triplets that sum to zero, with no duplicate triplets in the result.

Asked atAmazonMetaGoogleMicrosoft
step 1 / 65
-4
-1
-1
0
1
2
[0][1][2][3][4][5]
Brute force
▸
1given arr
2for i ← 0 to n − 3:
3    for j ← i + 1 to n − 2:
4        for k ← j + 1 to n − 1:
5            if arr[i] + arr[j] + arr[k] == 0:
6                record (i, j, k)
7dedupe results   // needs a set → O(n) extra space
state
  • target0
  • n6

line 1Find every unique triplet (a, b, c) in arr with a + b + c = 0.