周源当年的国家集训队作业，对ACM很有帮助的

题意:给你n个数,求出两两组合的最大公约数 类似打素数表的做法 -Meaning of the questions: to give you the number n, find greatest common divisor of a similar combination twenty-two hit the practice table of prime numbers

SGU 101 Domino 题解 能否找一条欧拉路将所有边走一遍，输出路径-SGU 101 Domino problem solution will be able to find an Euler path all the edges go again, the output path