QOJ.ac
QOJ
As a traditional event in the past years, join the IOI 2026 Prediction Game!
Top Rated Authored Problems
#353: qy511zzj
Authored Problems: : 0
#353: qya
Authored Problems: : 0
#353: qyan1023
Authored Problems: : 0
#353: qyby
Authored Problems: : 0
#353: qyc
Authored Problems: : 0
#353: Qyc_AK_NOI2022
Authored Problems: : 0
#353: qyc001
Authored Problems: : 0
#353: qyc123
Authored Problems: : 0
#353: QYCAKNOI2022
Authored Problems: : 0
#353: qycc
Authored Problems: : 0
#353: qyccc
Authored Problems: : 0
#353: QYcccc
Authored Problems: : 0
#353: Qycccccc
Authored Problems: : 0
#353: QYCtad
Authored Problems: : 0
#353: qyer
Authored Problems: : 0
#353: QYforVJ
Authored Problems: : 0
#353: qyh619718
Authored Problems: : 0
#353: QYHamster
Authored Problems: : 0
#353: Qyj
Authored Problems: : 0
#353: QYLSND
Authored Problems: : 0
#353: qym110809
Authored Problems: : 0
#353: qymx
Authored Problems: : 0
#353: qyockey
Authored Problems: : 0
#353: qypnf
Authored Problems: : 0
#353: qyqaq
Authored Problems: : 0
#353: QyQwQ
Authored Problems: : 0
#353: qyucheng
Authored Problems: : 0
#353: Qyun
Authored Problems: : 0
#353: qywqyw
Authored Problems: : 0
#353: qyy
Authored Problems: : 0
#353: qyy_
Authored Problems: : 0
#353: qyyyy_
Authored Problems: : 0
#353: qyyyyyy_
Authored Problems: : 0
#353: qyyyyyyy
Authored Problems: : 0
#353: qyyz002
Authored Problems: : 0
#353: qyyz003
Authored Problems: : 0
#353: qyzm
Authored Problems: : 0
#353: qyzy
Authored Problems: : 0
#353: qyzyq
Authored Problems: : 0
#353: qz_123
Authored Problems: : 0
#353: qz2003
Authored Problems: : 0
#353: qzc666
Authored Problems: : 0
#353: Qzcer
Authored Problems: : 0
#353: qzez
Authored Problems: : 0
对于无向图的情况，基尔霍夫矩阵为 $K=D-A$，其中 $D$ 为度数矩阵，$A$ 为邻接矩阵。树的个数为去掉 $K$ 一行一列的行列式的值。对于外向树，$D$ 为每个点的入边度数和，内向树相反。此时需要去掉根所在行列。BEST 定理：有向欧拉图的欧拉回路个数为：内向树个数乘以 $\prod\limits_{i=1}^{n}deg_i$，其中 $deg_i$ 为 $i$ 号点的度数。
#353: qzhfx
Authored Problems: : 0
#353: qzhwlzy
Authored Problems: : 0
#353: QZJ123456
Authored Problems: : 0
点赞过三万更新狗鲸鱼写真集
#353: qzl_114514
Authored Problems: : 0
#353: qzm123
Authored Problems: : 0
#353: qzmoot
Authored Problems: : 0
#353: Qzong
Authored Problems: : 0
#353: qzr
Authored Problems: : 0
#353: qzr_
Authored Problems: : 0
#353: qzs
Authored Problems: : 0
#353: qzuser
Authored Problems: : 0
#353: qzx
Authored Problems: : 0
#353: Qzxell
Authored Problems: : 0
#353: qzxhzxzs
Authored Problems: : 0
#353: qzy
Authored Problems: : 0
#353: Qzy___
Authored Problems: : 0
#353: qzymh
Authored Problems: : 0
#353: Qzyups
Authored Problems: : 0
#353: qzyz_wwq
Authored Problems: : 0
#353: qzyzni
Authored Problems: : 0
#353: qzzyq
Authored Problems: : 0
#353: R
Authored Problems: : 0
#353: R_8x
Authored Problems: : 0
#353: R05e_mary
Authored Problems: : 0
#353: R0okie
Authored Problems: : 0
#353: r0r_star
Authored Problems: : 0
#353: R0v
Authored Problems: : 0
#353: r0xy
Authored Problems: : 0
#353: r123
Authored Problems: : 0
#353: R1dicul3
Authored Problems: : 0
#353: r1sing
Authored Problems: : 0
#353: R1ST
Authored Problems: : 0
#353: r314
Authored Problems: : 0
#353: r314_qoj
Authored Problems: : 0
#353: r3ject
Authored Problems: : 0
#353: r3tgewr23
Authored Problems: : 0
#353: r4nd0m
Authored Problems: : 0
#353: R4y0n
Authored Problems: : 0
#353: r5b
Authored Problems: : 0
#353: R73757565
Authored Problems: : 0
#353: ra
Authored Problems: : 0
#353: Ra_ist
Authored Problems: : 0
#353: Ra16bit
Authored Problems: : 0
#353: ra1driar
Authored Problems: : 0
#353: Rabbert
Authored Problems: : 0
#353: Rabbi_Hasan162
Authored Problems: : 0
#353: RabbieWjy
Authored Problems: : 0
#353: rabbit_mygo
Authored Problems: : 0
#353: rabbit0909
Authored Problems: : 0
#353: rabbit0w0
Authored Problems: : 0
#353: rabbit111
Authored Problems: : 0
#353: rabbitohh
Authored Problems: : 0
#353: rabbyte
Authored Problems: : 0
#353: Rabeya
Authored Problems: : 0
#353: Rabilista
Authored Problems: : 0
#353: Rac
Authored Problems: : 0