update TODO

matrix tree theorem: done
RM-100-II: overcome by events

content/todo/_index.md

@@ -10,7 +10,7 @@ authors = ["xry111"]
 
 - [ ] Rethink linear algebra
 - [ ] Learn tensor algebra
-- [ ] Kirchhoff's matrix tree theorem ([Luogu 4336][lg4336])
+- [x] Kirchhoff's matrix tree theorem ([Luogu 4336][lg4336])
 - [ ] Trace of matrix (Problem J, 2019 ICPC Asia Regional Nanchang)
 
 # Physics
@@ -30,10 +30,3 @@ authors = ["xry111"]
 
 - [ ] Fix the prototype
 - [ ] Judging backend using systemd
-
-## RM-100-II
-
-- [ ] Utility for extracting data from binary stream
-- [ ] Experiment report
-
-[lg4336]: https://www.luogu.org/problem/P4336