### ZOJ3440. Detect the Virus II

[regex, topSort]

```# subparta:=fg|g
\$subparta = qr(fg|g);
# parta:=a|b|c
\$parta = qr{a|b|c};
# partb:=d|e[subparta]h
\$partb = qr{d|e(\$subparta)h};
# virus:=[parta][partb][partb]
\$virus = qr{(\$parta)(\$partb)(\$partb)};

printf 'abcdefghijklm' =~ \$virus ? "YES\n" : "NO\n";
printf 'nopqrstuvwxyz' =~ \$virus ? "YES\n" : "NO\n";
```

ZOJ在建站105个月之后迎来了第一百场比赛。

””\\(￣ー￣) (￣ー￣)//””

Let’s Celebrate the 100th Contest on ZOJ!
100A ZOJ3437 Very Hard Problem 6.89% (28/406)
100B ZOJ3438 Tripartite Graph 62.28% (71/114)
100C ZOJ3439 Substitution Cipher 7.86% (36/458)
100D ZOJ3440 Detect the Virus II 0.00% (0/26)
100E ZOJ3441 Crack Me II 2.06% (2/97)
100F ZOJ3442 Complex Calculator 0.00% (0/1)
100G ZOJ3443 Bessel Function II 0.00% (0/0)
100H ZOJ3444 An Unusual Problem 5.12% (2/39)
100I ZOJ3445 1KB 9.09% (4/44)

ZOJ Monthly, November 2010
A ZOJ3427 Array Slicing 21.05% (56/266)
B ZOJ3428 Bug Races 25.00% (2/8)
C ZOJ3429 Cube Simulation 22.94% (131/571)
D ZOJ3430 Detect the Virus 8.23% (40/486)
E ZOJ3431 Escape! 9.90% (21/212)
F ZOJ3432 Find the Lost Sock 18.38% (257/1398)
G ZOJ3433 Gu Jian Qi Tan 17.41% (39/224)
H ZOJ3434 Hiiragi’s Sticks 23.68% (9/38)
I ZOJ3435 Ideal Puzzle Bobble 4.87% (2/41)
J ZOJ3436 July Number 13.15% (15/114)

### ZOJ3427. Array Slicing

source code (ZOJ3427.cpp) [regex, simulation, slice, splice]

### ZOJ3428. Bug Races

source code (ZOJ3428.cpp) [Number theory, Pythagorean triple, Euclid's formula, counting]

ZOJ Monthly, October 2010
A ZOJ3406 Another Very Easy Task 34.45% (317/920)
B ZOJ3407 Doraemon’s Cake Machine 9.41% (55/584)
C ZOJ3408 Gao 8.38% (29/346)
D ZOJ3409 KKV 53.33% (8/15)
E ZOJ3410 Layton’s Escape 9.90% (99/999)
F ZOJ3411 Special Special Judge 18.87% (127/673)
G ZOJ3412 Special Special Judge II 30.23% (13/43)
H ZOJ3413 Special Special Judge III 4.79% (13/271)
I ZOJ3414 Trail Walk 34.31% (257/749)
J ZOJ3415 Zhou Yu 12.08% (11/91)

### ZOJ3406. Another Very Easy Task

source code (ZOJ3406.pl) [regex]

### ZOJ3407. Doraemon’s Cake Machine

source code (ZOJ3407.py) [math, enumeration]

ZOJ Monthly, September 2010
A ZOJ3396 Conference Call 10.73% (208/1937)
B ZOJ3397 Change the Major 11.20% (13/116)
C ZOJ3398 Warden 1.50% (2/133)
D ZOJ3399 Classes Division 6.87% (9/131)
E ZOJ3400 Treasure Hunting 3.67% (16/435)
F ZOJ3401 Guitar 34.04% (96/282)
G ZOJ3402 Marble 10.00% (2/20)
H ZOJ3403 Strange Calendar III 8.78% (194/2208)
I ZOJ3404 Sticker 22.22% (2/9)
J ZOJ3405 Counting Factor Trees 11.62% (137/1179)