# How to Show Subset Sum $\le_p$ 3-Partition

Given a set of integers S (positive and negative, may contain duplicates) can S be divided into three disjoint subsets that all sum to the same value? Prove this problem is NP-complete.

Is it possible to show directly that Subset Sum $$\le_p$$ 3-Partition, or would I have to do

Subset Sum $$\le_p$$ Partition $$\le_p$$ 3-Partition?