Once you submit a pull request it must be reviewed by at least 2 mentors before being merged. You must put your name and roll number as comment in the pull request to make sure that it is reflected in the leaderboard. There are 4 types of pull requests anyone contributing to the code should submit. The type of pull request will be mentioned by the reviewers.
Contain any contructive change to the repo including any single character changes.
Contain changes in the documentation of at least one function and adhere to the existing format.
Contain at least some changes to code. Including optimizations.
Full implementations of incomplete functions or improvement in the compilation command.
Also don't be disappointed if you recieve some strict code reviews. ;-)