Research Papers for High-School/Undergraduate Students

Infoarena tries to build up a page containing links to some algorithms-related research papers, presenting results that may be understood (and even used in programming contests) by high-school and undergraduate students. There are already several nice papers listed there (selected by Mihai Patrascu, Cosmin Negruseri and others). I intend to add to that list some of the papers that influenced me in the past (as far as they are available online); moreover I will add any paper I read and consider as being suitable for this page.