本文将常见的设计剪枝判断的思路分成可行性剪枝和最优性剪枝两大类，并结合上述三个原则分别以一道竞赛题为例作了说明，最后对剪枝方法作了一些总结。-this paper the design of common pruning judgment ideas into pruning feasibility and optimality pruning two categories, and the combination of these three principles were in a contest and that as an example, the last pair of pruning methods some conclusions.