An input can be large while the feature that makes it difficult is small. Parameterized algorithms ask how running time depends on that feature as well as on input size, and use the resulting structure to approach problems that are hard in general.
This course develops the main algorithmic techniques through concrete problems: kernelization, branching, iterative compression, randomization, treewidth and dynamic programming, separators, integer programming, algebraic methods, and representative sets. The final lectures introduce parameterized reductions and hardness.
The NPTEL course is taught by Neeldhara Misra and Saket Saurabh. It is intended as a follow-up to a first course in data structures and algorithms.