@[NaCly_Fish](/space/show?uid=115864) %%%
by ChenHacker @ 2018-11-23 22:23:16
@[ChenHacker](/space/show?uid=92288) QAQ
by NaCly_Fish @ 2018-11-23 22:31:18
@[NaCly_Fish](/space/show?uid=115864) ~~这不是莫队吗~~
by Juanzhang @ 2018-11-23 23:10:02
@[小光](/space/show?uid=73934) 求助怎么搞
by NaCly_Fish @ 2018-11-23 23:17:53
@[NaCly_Fish](/space/show?uid=115864) 莫队
by Juanzhang @ 2018-11-23 23:18:59
@[小光](/space/show?uid=73934) 稍微详细一点吧，谢谢大佬orz
by NaCly_Fish @ 2018-11-23 23:19:57
@[NaCly_Fish](/space/show?uid=115864)
by Juanzhang @ 2018-11-23 23:26:49
$\displaystyle\sum_{i=0}^{k+1}{C_{n}^i}=(\displaystyle\sum_{i=0}^{k}{C_{n}^i})+C_n^{k+1}$
$\displaystyle\sum_{i=0}^{k-1}{C_{n}^i}=(\displaystyle\sum_{i=0}^{k}{C_{n}^i})+C_n^{k-1}$
by Juanzhang @ 2018-11-23 23:28:00
$\displaystyle\sum_{i=0}^{k}{C_{n+1}^i}\;\&\; \displaystyle\sum_{i=0}^{k}{C_{n-1}^i}$
考虑杨辉三角
by Juanzhang @ 2018-11-23 23:28:47
@[小光](/space/show?uid=73934) 第二个式子确定没写错吗QAQ
by NaCly_Fish @ 2018-11-23 23:30:23