This Pull Request is for HacktoberFest 2020

Description of Change

Checklist

• Added description

Welcome to JavaScript community

Describe your change:

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that p

Add quickselect algorithm. Quickselect is a selection algorithm to find the kth smallest element in an unordered list.

Description of Change

References

Checklist

RDF::Mean() uses plain doubles. That's better than float, but far from stable. When you run with IMT, it's actually more accurate than without, because less numbers go into one accumulator, and each running sum remains smaller. So IMT/NoIMT can break your tests (even different TBB scheduling does).

It was creating problems already in this simple test (note that the precision threshold for tes

The igraph tutorial (here online, source file here) should be reviewed:

• Is it up to date?
• Is it understandable by a newcomer?
• Are essential points unexplained or missing?

Ideally, this should be done by someone who is new to using igraph, to get a fresh perspective. Th