2019银川网络赛

??A. Maximum Element In A Stack

??B. Rolling The Polygon

??C. Caesar Cipher

??D. Take Your Seat

E. 2-3-4 Tree

??F. Moving On

G. Factories　　

树形DP + 背包

https://blog.csdn.net/dllpXFire/article/details/81085093

https://blog.csdn.net/starlet_kiss/article/details/100176118

??H. Fight Against Monsters

I. Bubble Sort

J. Nested Triangles

K. Vertex Covers

L. Continuous Intervals

单调栈

https://www.cnblogs.com/Pneuis/p/9332445.html

M. Acyclic Orientation

原文地址：https://www.cnblogs.com/ckxkexing/p/11440674.html