Subset Sum: Find All Valid Subsets

Given a list of integers and a target sum \(T\), your task is to find all subsets of the list whose elements sum exactly to \(T\). Each valid subset should be printed in a separate line with its elements separated by a single space. If there is no valid subset, print a single line containing "[]".

Formally, given an integer \(T\) and a list \(A = [a_1, a_2, \dots, a_N]\), find all subsets \(S \subseteq A\) such that:

[ \sum_{x \in S} x = T ]

You may output the subsets in any order.

inputFormat

The input is read from stdin and has the following format:

1. The first line contains two integers \(N\) and \(T\), where \(N\) is the number of elements and \(T\) is the target sum.
2. The second line contains \(N\) space-separated positive integers.

outputFormat

For each valid subset, print a line with the subset's elements separated by a single space. If no valid subset exists, output a single line containing "[]".

## sample

4 5
1 2 3 4

1 4
2 3

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