Efficiency slide (last slide):

• The slide might be confusing and will be changed into a more appropriate format. Left-top, you see "All (One solution)" which explains the meaning of the numbers of the efficiency table. Note that we only solved the exercises for one solution and did not generate all solutions by further backtracking/jumping (We leave this as an exercise to you). Thus, in fact, the numbers between the brackets are relevant to the exercises, which is the confusing part of the slide.
• To calculate the numbers, we mean by opened nodes all nodes of which the children are (partially) explored. So, no leaf node (thus also no NG) is taken into account. By checks, we mean all binary checks and all unary checks that fail. By NG, we mean the cost of calculating and using No-Goods, which can be arbitrary large.