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We introduce LeetCodeDataset, a high-quality benchmark for evaluating and training code-generation models, addressing two key challenges in LLM research: the lack of reasoning-focused coding benchmarks and self-contained training testbeds. By curating LeetCode Python problems with rich metadata, broad coverage, 100+ test cases per problem, and temporal splits (pre/post July 2024), our dataset enables contamination-free evaluation and efficient supervised fine-tuning (SFT). Experiments show reasoning models significantly outperform non-reasoning counterparts, while SFT with only 2.6K model-generated solutions achieves performance comparable to 110K-sample counterparts. The dataset and evaluation framework are available on Hugging Face and Github.

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AdaptiveStep: Automatically Dividing Reasoning Step through Model Confidence

Published in , 2025

Current approaches for training Process Reward Models (PRMs) often involve breaking down responses into multiple reasoning steps using rule-based techniques, such as using predefined placeholder tokens or setting the reasoning step’s length into a fixed size. These approaches overlook the fact that specific words do not typically mark true decision points in a text. To address this, we propose AdaptiveStep, a method that divides reasoning steps based on the model’s confidence in predicting the next word. This division method provides more decision-making information at each step, enhancing downstream tasks, such as reward model learning. Moreover, our method does not require manual annotation. We demonstrate its effectiveness through experiments with AdaptiveStep-trained PRMs in mathematical reasoning and code generation tasks. Experimental results indicate that the outcome PRM achieves state-of-the-art Best-of-N performance, surpassing greedy search strategy with token-level value-guided decoding, while also reducing construction costs by over 30% compared to existing open-source PRMs. In addition, we provide a thorough analysis and case study on the PRM’s performance, transferability, and generalization capabilities.

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Breaking the Attention Trap in Code LLMs: A Rejection Sampling Approach to Enhance Code Execution Prediction

Published in , 2025

Code-specific Large Language Models (Code LLMs) have greatly improved performance across code-related tasks, offering substantial benefits in practical applications. However, existing research reveals significant performance bottlenecks in Code Execution tasks, which requires models to predict the execution results of given code snippets. This study identifies that, the Attention Trap phenomenon in training data constitutes a key constraint on model performance. To address this phenomenon, we propose the Attention Cracking with Rejection Sampling (AC-RS) method. The method first applies structural optimization to training data to eliminate attention traps. Then, it conducts secondary training on the outputs generated by the fine-tuned model to mitigate potential negative impacts from manual data intervention. Experimental results show that AC-RS significantly enhances the accuracy of Code Execution while preserving models’ original capabilities. Notably, the optimized 7B model achieves Code Execution accuracy comparable to 32B model and GPT-4o.

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Undergraduate course, University 1, Department, 2014

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Workshop, University 1, Department, 2015

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Yunhui Xia

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