Three Sum Problem

You are given an array of integers. Your task is to find all unique triplets \( (a, b, c) \) such that they satisfy the equation \(a + b + c = 0\). Each triplet should be output in non-decreasing order (i.e. \(a \le b \le c\)) and the list of triplets should be sorted in lexicographical order. Duplicate triplets are not allowed.

Input: The input is given via standard input (stdin). The first line contains an integer \(n\), representing the number of elements. The second line contains \(n\) space-separated integers, which are the elements of the array.

Output: For each unique triplet found, print the three integers separated by a space on a single line. If no such triplet exists, print nothing.

Note: Use an efficient approach such as sorting combined with the two-pointer method.

inputFormat

The first line contains a single integer \(n\) \( (0 \le n \le 10^4)\), denoting the number of elements in the array. The second line contains \(n\) space-separated integers, each representing an element of the array.

outputFormat

For every unique triplet \((a, b, c)\) that sums to zero, output a line with the three numbers separated by a space in non-decreasing order. The triplets themselves should be sorted lexicographically. If there is no such triplet, output nothing.

## sample

6
-1 0 1 2 -1 -4

-1 -1 2
-1 0 1

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