第一层内容：杂题

    接上一篇博客，这篇课文其实没讲什么内容（杂题要是能讲出固定的算法我也就服了。。。），诸位有兴趣的就看看吧，聊以自慰。

Ad Hoc Problems

`Ad hoc' problems are those whose algorithms do not fall into standardcategories with well-studied solutions. Each ad hoc problem is different; nospecific or general techniques exist to solve them.

Of course, this makes the problems the `fun' ones, since each one presentsa new challenge. The solutions might require a novel data structure or anunusual set of loops or conditionals. Sometimes they require specialcombinations that are rare or at least rarely encountered.

Ad hoc problems usually require careful reading and usually yield to anattack that revolves around carefully sequencing the instructions given in theproblem.

Ad hoc problems can still require reasonable optimizations and at least adegree of analysis that enables one to avoid loops nested five deep, forexample.

More ad hoc problems appear on this web site than any other kind ofproblem. Always be ready for an ad hoc problem if you can not classify aproblem as one of the other standard types (to be listed later).