补题栈

Problem B: 序列

http://xsy.gdgzez.com.cn/JudgeOnline/problem.php?cid=1922&pid=1

Problem C: 交换

http://xsy.gdgzez.com.cn/JudgeOnline/problem.php?cid=1921&pid=2

Problem A: 排列

http://xsy.gdgzez.com.cn/JudgeOnline/problem.php?cid=1920&pid=0

Problem B: ±AB

http://xsy.gdgzez.com.cn/JudgeOnline/problem.php?cid=1920&pid=1

Problem B: Gateau

http://xsy.gdgzez.com.cn/JudgeOnline/problem.php?cid=1916&pid=1

Nim on Towers of Hanoi

https://pe.xiaoyaowudi.com/problem=806

CF1034D Intervals of Intervals

https://www.luogu.com.cn/problem/CF1034D