The Lattice Method
Basic

Video tutorial

Lecture Notes

The lattice method is extremely intuitive but also a powerful and versatile technique. Some of the AIME and Exeter problems can be solved using this method.

Examples

(4724) $\textbf{Number of Routes}$ The shortest route from point $A$ to $B$ takes $10$ steps. How many such routes are there that do not pass point $C$? |

Comments

In essence, this lattice method is similar to the Knives and Balls (Stars and Sticks) method which will be discussed later in this course. Both enumerate all the intermediate steps and results in a systematic way to get the final answer.