| 1 | 
https://codeforces.com/problemset/problem/485/D | 
 | 
中等 | 
| 2 | 
https://codeforces.com/problemset/problem/459/B | 
 | 
简单 | 
| 3 | 
https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1917 | 
 | 
较简单 | 
| 4 | 
https://codeforces.com/problemset/problem/526/C | 
 | 
中等 | 
| 5 | 
https://acm.hdu.edu.cn/showproblem.php?pid=5719 | 
 | 
较难 | 
| 6 | 
http://poj.org/problem?id=1152 | 
 | 
中等 | 
| 7 | 
http://poj.org/problem?id=1061 | 
exgcd板子题 | 
中等 | 
| 8 | 
http://bailian.openjudge.cn/practice/4117?lang=en_US | 
整数划分板子 | 
较简单 | 
| 9 | 
http://poj.org/problem?id=1664 | 
放抽屉问题板子 | 
较简单 | 
| 10 | 
https://www.51nod.com/Challenge/Problem.html#problemId=1073 | 
约瑟夫问题数学解 | 
较简单 | 
| 11 | 
https://acm.hdu.edu.cn/showproblem.php?pid=2032 | 
输出杨辉三角 | 
简单 | 
| 12 | 
https://acm.hdu.edu.cn/showproblem.php?pid=2050 | 
卡特兰数板子题 | 
较简单 |