Detour: Graphs

What “graph” means in this course

The use of the word “graph” in this course is different from its use in high school mathematics; we don’t mean a chart of data. You can think of a graph as a diagram showing cities connected by roads.

The first panel in the below figure shows a 4 × 4 chessboard with the four corner squares removed. A knight can move two steps in any of four directions (left, right, up, and down) followed by one step in a perpendicular direction. For example, a knight at square 1 can move to square 7 (two down and one left), square 9 (two down and one right), or square 6 (two right and one down).