QOJ.ac
QOJ
#194: ningago
Accepted: : 290
#194: ucup-team7345
Accepted: : 290
#196: ideograph_advantage
Accepted: : 289
#196: ucup-team5217
Accepted: : 289
#196: wsc2008
Accepted: : 289
#199: ucup-team7545
Accepted: : 288
#199: ucup-team896
Accepted: : 288
#201: 0000pnc
Accepted: : 287
#201: lgvc
Accepted: : 287
#201: ucup-team7398
Accepted: : 287
#204: rqoi031
Accepted: : 283
#205: jiangxinyang
Accepted: : 282
#206: ucup-team6590
Accepted: : 281
#206: ucup-team7502
Accepted: : 281
#208: CHD
Accepted: : 280
即使雨永不停歇地下，也要在未曾被雨浸透的角落保有属于自己的一小片虹。
#208: ucup-team5015
Accepted: : 280
#210: A_programmer
Accepted: : 279
#210: ucup-team1817
Accepted: : 279
#212: ucup-team4217
Accepted: : 278
#213: Dinal
Accepted: : 276
#213: ucup-team045
Accepted: : 276
#215: addiyoue
Accepted: : 273
You Know Who
#215: dxbt
Accepted: : 273
#215: ucup-team1525
Accepted: : 273
#218: Forever_Young
Accepted: : 271
#219: AFewSuns
Accepted: : 269
$\displaystyle\sum_{n \geq 0}{(x+y)^n\frac{u^n}{n!}}=\sum_{k \geq 0}\frac{x}{x-kz}(x-kz)^k\frac{u^k}{k!}\sum_{l \geq 0}\frac{(y+kz)^l}{l!}u^l$
#219: ucup-team3099
Accepted: : 269
#221: complexor
Accepted: : 268
#222: LuSter_M
Accepted: : 266
#222: specialuser
Accepted: : 266
#224: ucup-team122
Accepted: : 265
#225: ucup-team3670
Accepted: : 263
#226: ucup-team110
Accepted: : 262
#227: LosMem
Accepted: : 260
#228: He_Ren
Accepted: : 259
#228: hydd
Accepted: : 259
But are we all lost stars trying to light up the dark?
#228: NKheyuxiang
Accepted: : 259
#228: ucup-team1447
Accepted: : 259
没队要
#228: wangjunrui
Accepted: : 259
丢掉幻想，准备斗争！！！
#233: ucup-team4527
Accepted: : 257
#233: ucup-team5071
Accepted: : 257
#235: ucup-team3515
Accepted: : 251
#236: __jk__
Accepted: : 250
#237: ucup-team3097
Accepted: : 249
#238: hshhh
Accepted: : 248
#238: IllusionaryDominance
Accepted: : 248
#238: tricyzhkx
Accepted: : 248
#238: ucup-team180
Accepted: : 248
#242: cooluo
Accepted: : 247
π⁴+π⁵≈e⁶ | Per Aspera Ad Astra
#242: hui
Accepted: : 247
#242: ucup-team2307
Accepted: : 247
#245: ucup-team2172
Accepted: : 246
法克皮百吨
#246: 617lyq
Accepted: : 245
#246: ucup-team1293
Accepted: : 245
#246: wcyQwQ
Accepted: : 245
#249: Misuki
Accepted: : 244
$\mathbb{C}[x]/(x^{2^n} - 1) \cong \mathbb{C}[x]/(x - \omega) \times \mathbb{C}[x]/(x - \omega^2) \times \ldots\times \mathbb{C}[x]/(x - \omega^{2^n})$
#249: ucup-team7623
Accepted: : 244
#251: jrjyy
Accepted: : 243
#251: Register
Accepted: : 243
#251: ucup-team2045
Accepted: : 243
#254: lunchbox
Accepted: : 242
#255: jimmyywang
Accepted: : 241
#255: std
Accepted: : 241
哼
#255: Whales
Accepted: : 241
#258: carrotqq
Accepted: : 240
#259: CSQ
Accepted: : 239
#259: rizynvu
Accepted: : 239
#259: ucup-team267
Accepted: : 239
哈姆。
#262: thomaswmy
Accepted: : 237
#262: ucup-team3734
Accepted: : 237
#264: iee
Accepted: : 236
#264: ucup-team135
Accepted: : 236
#266: ETK
Accepted: : 235
「我是星 我愿投身前途未卜的群星，为梦长明。」
#266: huaxiamengjin
Accepted: : 235
#266: ucup-team3627
Accepted: : 235
#269: ucup-team7256
Accepted: : 234
#269: UESTC_BYR
Accepted: : 234
#271: Seniorious
Accepted: : 232
We do not know and will not know
#271: wsxcb
Accepted: : 232
#273: ucup-team3586
Accepted: : 231
#273: ucup-team5984
Accepted: : 231
#275: Euphoria_
Accepted: : 230
Orz ian_HLX
#275: ucup-team5008
Accepted: : 230
#277: tzl_Dedicatus545
Accepted: : 229
忙碌着 无为着 继续
#278: DitaMirika
Accepted: : 228
Face the fear,make the future.
#278: makrav
Accepted: : 228
#278: qzez
Accepted: : 228
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。
#278: ucup-team4269
Accepted: : 228
#278: ucup-team6719
Accepted: : 228
Are we robots?
#278: XY_Eleven
Accepted: : 228
#284: cmll02
Accepted: : 227
#284: KobicGend
Accepted: : 227
#286: chenshi
Accepted: : 225
#286: SirTechnical
Accepted: : 225
#286: ushg8877
Accepted: : 225
#289: ljw12345
Accepted: : 224
#289: SoyTony
Accepted: : 224
真実はいつもひとつ
#289: ucup-team6879
Accepted: : 224
#292: 8BQube
Accepted: : 222
#292: Auto_7
Accepted: : 222