Question: 1. We claimed that the column-position list (3,2,5,6,2,7,1,8) had two coins on the same diagonal. Which two and why?
2. Why is this approach called backtracking?
3. Draw all trees on seven vertices.
4. Show that the average degree of a tree is less than 2. Explain how this result provides a proof that every tree has at least one leaf.