SPaR: Self-Play with Tree-Search Refinement to Improve Instruction-Following in Large Language Models - Cheng, Jiale; Liu, Xiao; Wang, Cunxiang; Gu, Xiaotao; Lu, Yida; Zhang, Dan; Dong, Yuxiao; Tang, Jie; Wang, Hongning; Huang, Minlie (International Conference on Learning Representations, 2025)