This repo contains solution of some problems from spoj/topcoder etc. It uses chelper in intellij.
To run any of the java files, you will need chelper installed(https://www.jetbrains.com/help/idea/2016.3/installing-updating-and-uninstalling-repository-plugins.html). Once you import this project, you will be able to run the java files.
If intellij complains, about any class missing, that is because if cannot find chelper jar as a dependency. Just open chelper settings, you will see that the settings are populated with some values (they come from the chelper.properties file in the repo). just save it. that brings the chlper jar in.