Teaching Transformers to Solve Combinatorial Problems through Efficient Trial & Error

Published: 18 Sept 2025, Last Modified: 29 Oct 2025NeurIPS 2025 posterEveryoneRevisionsBibTeXCC BY 4.0
Keywords: LLMs, Transformers, Combinatorial, Sudoku, SAT
TL;DR: This work introduces a method for NP-class combinatorial problems using a vanilla Transformer. By combining Sudoku rules and guesses, the approach achieves SOTA results (99.8%). Solution length is analyzed via the Min-Sum Set Cover problem.
Abstract: Despite their proficiency in various language tasks, Large Language Models (LLMs) struggle with combinatorial problems like Satisfiability, Traveling Salesman Problem, or even basic arithmetic. We address this gap through a novel approach for solving problems in the class NP. We focus on the paradigmatic task of Sudoku and achieve state-of-the-art accuracy (99\%) compared to prior neuro-symbolic approaches. Unlike prior work that used custom architectures, our method employs a vanilla decoder-only Transformer (GPT-2) without external tools or function calling. Our method integrates imitation learning of simple Sudoku rules with an explicit Depth-First Search (DFS) exploration strategy involving informed guessing and backtracking. Moving beyond imitation learning, we seek to minimize the number of guesses until reaching a solution. We provide a rigorous analysis of this setup by formalizing its connection to a contextual variant of $\textit{Min-Sum Set Cover}$, a well-studied problem in algorithms and stochastic optimization.
Primary Area: Deep learning (e.g., architectures, generative models, optimization for deep networks, foundation models, LLMs)
Submission Number: 16961
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