DARTS: Diversity-Aware Reasoning Tree Search for Test-Time Scaling

Kaifeng Liu, Shijie Wang, Yuanxing Liu, Yang Liu, Xinyi Wang, Haozheng Hou, Biqing Qi, Weinan Zhang, Ting Liu


Abstract
Test-time tree search improves the reasoning capability of large language models under fixed inference budgets. However, existing solution-level MCTS often suffers from local homogenization: once a promising solution pattern is found, subsequent search tends to refine nearby variants rather than explore distinct reasoning paths. This wastes computation on redundant candidates and limits solution-space coverage. To address this problem, we propose Diversity-Aware Reasoning Tree Search (DARTS), a Bayesian tree-search framework that treats reasoning-path diversity as an explicit search objective. DARTS separates expansion into local refinement and orthogonal regeneration, and updates action posteriors using a joint reward over task quality and reasoning-path diversity. On LiveCodeBench and CodeContests, DARTS achieves the best exploration performance and produces more diverse correct solutions. With half the budget, it matches or exceeds the strongest tree-search baseline in four of six settings. On molecular optimization tasks, DARTS improves both optimization quality and structural diversity, suggesting cross-domain transfer.
Anthology ID:
2026.findings-emnlp.1161
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
24577–24600
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1161/
DOI:
Bibkey:
Cite (ACL):
Kaifeng Liu, Shijie Wang, Yuanxing Liu, Yang Liu, Xinyi Wang, Haozheng Hou, Biqing Qi, Weinan Zhang, and Ting Liu. 2026. DARTS: Diversity-Aware Reasoning Tree Search for Test-Time Scaling. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 24577–24600, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DARTS: Diversity-Aware Reasoning Tree Search for Test-Time Scaling (Liu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1161.pdf