Source Code Similarity Detection Using Adaptive Local Alignment of Keywords

Program similarity checking is an important application of programming education fields. Local alignment is one of the typical algorithms for comparing two strings. However local alignment based comparison does not reflect the weights of program keywords. This paper introduces an adaptive local alignment which reflects the frequencies of keywords to the similarity matrix. We experimented this method using a set of programs submitted to more than 10 real programming contests. The experimental result shows that the adaptive local alignment is more robust than greedy-string-tiling adopted in JPlag.