6.006 Introduction to Algorithms (Fall 2011, MIT OCW). Taught by Professor Erik Demaine and Professor Srinivas Devadas, this course provides an introduction to mathematical modeling of computational problems. It covers the common algorithms, algorithmic paradigms, and data structures used to solve these problems. The course emphasizes the relationship between algorithms and programming, and introduces basic performance measures and analysis techniques for these problems.
(from ocw.mit.edu)
Lecture 03 - Insertion Sort, Merge Sort
Sorting is introduced, and motivated by problems that become easier once the inputs are sorted. The lecture covers insertion sort, then discusses merge sort and analyzes its running time using a recursion tree.