His research interests are in graph algorithms, discrete optimization, and computational geometry. He has published about 150 journal and conference papers, and several book chapters on these topics. He is an editor for the journal Algorithmica, Networks, International Journal on Foundations of Computer Science, problems Editor for ACM Trans. on Algorithms, and a columnist for SIGACT News. He has served on several program committees including SODA 1997, APPROX 1999, APPROX 2000 (chair), STOC 2003, PODS 2006, SODA 2007, APPROX 2010, ESA 2010.
He received the National Science Foundation's Career Development Award, several Dept. Teaching Awards, the Dean's Teaching Excellence Award and also a CTE-Lilly Teaching Fellowship. In 2003, he and his students were awarded the "Best newcomer paper" award for the ACM PODS Conference. He received the University of Maryland's Distinguished Scholar Teacher Award in 2007, as well as a Google Research Award. He graduated at the top of the Computer Science Class from IIT-Kanpur.