c# - Regex blocks of permutations -

thanks kobi resolve problem of checking permutations without repetition given string "abbc". solution

(?:(?<a>a)|(?<b>b)|(?<c>c)){4}(?<-a>)(?<-b>){2}(?<-c>) 

the expression has have 1 "a", 2 "b" , 1 "c" in 4 consecutive characters.

now need more complicated, need check expression 2 blocks of permutations:

1. in first 6 positions has find permutations of "abccc" adding each 1 character in 3rd position can of them (a, b or c).
2. in second block has find permutations of "abccc"

i don't know if have explained myself well, but:

1. for first 6 positions has have 1 a, 1 b, 3 c , in 3rd position value (a,b or c) no matter order except 3rd position can any
2. for next 5 positions has have 1 a, 1 b , 3 c no matter order.

i'm trying explain best way possible. i'm sorry looked copy-paste not.

the regex i'm looking "abxccc-abccc" x a, b or c , - separate 2 blocks, although i'm adding - because first 6 characters have combinations , last 5 same.

it doesn't have way, similar, example. "aabxxcc-abbc" example.

it simple adapt the previous pattern new one.

the second block straightforward:

(?:(?<a>a)|(?<b>b)|(?<c>c)){5}(?<-a>)(?<-b>)(?<-c>){3} 

next, thing need know can specify same group more once. explained in martin büttner's answer, i've linked before.

so, first block, [abc] on first position, can written as:

(?:(?<a>a)|(?<b>b)|(?<c>c)){2}[abc](?:(?<a>a)|(?<b>b)|(?<c>c)){3}(?<-a>)(?<-b>)(?<-c>){3} 

combined:

(?:(?<a>a)|(?<b>b)|(?<c>c)){2}[abc](?:(?<a>a)|(?<b>b)|(?<c>c)){3}(?<-a>)(?<-b>)(?<-c>){3}-(?:(?<a>a)|(?<b>b)|(?<c>c)){5}(?<-a>)(?<-b>)(?<-c>){3} 

or, ignore whitespace flag:

(?:(?<a>a)|(?<b>b)|(?<c>c)){2}  # match 2 a, b, or c's [abc]                           # match a, b, or c, don't push stack. (?:(?<a>a)|(?<b>b)|(?<c>c)){3}  # match 3 a, b, or c's (?<-a>)(?<-b>)(?<-c>){3}        # check we've matched 1 a, 1 b , 3 c's. -                               # match dash (?:(?<a>a)|(?<b>b)|(?<c>c)){5}  # match 5 a, b, or c's (?<-a>)(?<-b>)(?<-c>){3}        # check we've matched 1 a, 1 b , 3 c's. 

this not elegant (it has repetition), should still simple understand next step of previous question.

working example @ regex storm