2022 senior S3 Good Samples
constructive algorithm
2021 senior S3 Lunch Concert
binary search
2020 senior S3 searching for strings
two pointer
2019 senior S3 Arithmetic Square
2018 senior S3 robot theieves
BFS
2017 senior S3 Nailed it!
http://www.usaco.org/index.php?page=viewproblem2&cpid=739
enumeration
http://www.usaco.org/index.php?page=viewproblem2&cpid=941
weird problem