A use python and c++, and there are code before and agter learn from Google Analysis.
B only contain c++ and code after learn from Google Analysis. In B practice, I learned knowledge about binary serach, Binary Indexed Tree : Range Updates and Point Queries, prefix sum. Thanks for geeksforgeeks and basasuya.
C The first time solve dp, C is a copy from [2]. And then i find two problem and try to solve them. The problems are [3] and [4].
Mainly reference:
[1] https://www.geeksforgeeks.org/binary-indexed-tree-range-updates-point-queries/
[2] http://www.cnblogs.com/Basasuya/archive/2018/10/22/9833499.html
[3] https://blog.csdn.net/qq_35935435/article/details/58593486
[4] https://blog.csdn.net/Netown_Ethereal/article/details/24297747