Abstract
With the widespread application of computer technology in engineering education, Online Judge (OJ) systems have become an important platform for programming teaching. OJ systems provide a platform for learners to practice programming skills, submit solutions, and receive feedback. They offer a conducive environment for learners to engage in hands-on coding exercises and enhance their programming abilities. This article explores the use of OJ systems as a software tool for enhancing programming education in engineering. It investigates how the difficulty and order of programming problems affect the users' behavior, performance, and cognitive load in OJ environments. The research data were sourced from Project_CodeNet. Using statistical methods, such as Spearman correlation analysis and differential analysis, the study reveals the factors that influence the users' submission situations, answer order, and learning outcomes. The findings provide useful implications for OJ system developers, teachers, and learners in designing, implementing, and using OJ systems for programming education in engineering. The study suggests that problem difficulty and order should be considered and adjusted according to the users' abilities and progress, to provide appropriate challenges and support, balance the cognitive load, and improve the programming skills of the users.