组合几何诞生于 2 0世纪中叶 ,是用组合数学的成果来解决几何学中的问题 ,主要研究几何图形的拓扑性质和有限制条件的欧几里德性质 .组合几何以其内容丰富 ,题目新颖 ,难度有层次而在竞赛数学中异军突起 .分类是一种重要的数学思想方法 ,它分化了问题的难度 ,对每一子问题而言 Composite geometry was born in the middle of the 20th century. It uses the results of combinatorial mathematics to solve problems in geometry. It mainly studies the topological nature of geometrical graphs and the Euclidean nature of restricted conditions. Combinatorial geometry is rich in content and novel in topics. , difficulty leveled and emerging in the race of mathematics. Classification is an important mathematical thinking method, which divides the difficulty of the problem, for each sub-question