Eigenvectors are vectors that change at most by a scalar factor when a linear transformation is applied to them. They point in the direction of stretching and their corresponding eigenvalue is the factor by which they are stretched. Negative eigenvalues reverse the direction of the vector.

CS 168 provides a comprehensive introduction to modern algorithm concepts, covering hashing, dimension reduction, programming, gradient descent, and regression. It emphasizes both theoretical understanding and practical application, with each topic complemented by a mini-project. It's suitable for those who have taken CS107 and CS161.