Confusing Alphabet Staircase

Question

Given no input, output this interesting alphabet pattern in either case (the case has to be consistent) via an accepted output method:

A
AB
ACBC
ADBDCD
AEBECEDE
AFBFCFDFEF
AGBGCGDGEGFG
AHBHCHDHEHFHGH
AIBICIDIEIFIGIHI
AJBJCJDJEJFJGJHJIJ
AKBKCKDKEKFKGKHKIKJK
ALBLCLDLELFLGLHLILJLKL
AMBMCMDMEMFMGMHMIMJMKMLM
ANBNCNDNENFNGNHNINJNKNLNMN
AOBOCODOEOFOGOHOIOJOKOLOMONO
APBPCPDPEPFPGPHPIPJPKPLPMPNPOP
AQBQCQDQEQFQGQHQIQJQKQLQMQNQOQPQ
ARBRCRDRERFRGRHRIRJRKRLRMRNRORPRQR
ASBSCSDSESFSGSHSISJSKSLSMSNSOSPSQSRS
ATBTCTDTETFTGTHTITJTKTLTMTNTOTPTQTRTST
AUBUCUDUEUFUGUHUIUJUKULUMUNUOUPUQURUSUTU
AVBVCVDVEVFVGVHVIVJVKVLVMVNVOVPVQVRVSVTVUV
AWBWCWDWEWFWGWHWIWJWKWLWMWNWOWPWQWRWSWTWUWVW
AXBXCXDXEXFXGXHXIXJXKXLXMXNXOXPXQXRXSXTXUXVXWX
AYBYCYDYEYFYGYHYIYJYKYLYMYNYOYPYQYRYSYTYUYVYWYXY
AZBZCZDZEZFZGZHZIZJZKZLZMZNZOZPZQZRZSZTZUZVZWZXZYZ

Trailing spaces and newlines are acceptable, standard loopholes are disallowed, and this happens to be code-golf, so the shortest answer in bytes wins!

Answer 1

><>, 47 bytes

d2*:1-v
-&$:?!\$:&$:1
1-:?!v\69*-$1-:
+*88~< 1o

Try it online!

How It Works:

d2*:1-v Initialise the stack with 26 (outer loop counter) and 26-1 (inner loop counter)
....
....
....

....
-&$:?!\$:&$:1 Repeatedly make copies of both counters
....          And decrement the inner loop counter
....          Go to third line when inner loop counter is 0

....            Add -54 to the stack (for the newline) and decrement the outer loop counter
....            Initialise the inner loop counter as outer-1
1-:?!v\69*-$1-: If the inner counter is 0, go to the fourth line, else back to the second.
....

....
....      
....      Transform numbers and -54s into letters and newlines by adding 64
+*88~< 1o Output each character until it runs out of stack and errors

Answer 2

Canvas, 11 10 bytes

Ｚ｛Ｚ²╷ｍ¹＊×］

Try it here!

Answer 3

GNU M4, 119 bytes

The worst so far. Well, time's already spent…

define(f,`ifelse($1,$2,,`format(%c%c,$1,$2)`'f(incr($1),$2)')')define(g,`f(65,$1)ifelse($1,90,,`
g(incr($1))')')A
g(66)

Answer 4

J, 38, 33 30 bytes

-5 bytes thanks to Bolce Bussiere

-3 bytes thanks to FrownyFrog

'A ',}.(}:,@,.{:)\(65+i.26){a.

How?

(65+i.26){a. - uppercase alphabet

\ - prefixes

(}:,@,.{:) - drops the last letter from each prefix and inserts it between the remaining letters

}. drops the leading row since it's empty (not "A")

, - append

'A ' - "A"

Try it online!

Answer 5

Husk, 13 bytes

Γ·:mhSzJḣ…"AZ

Try it online!

Explanation

This leading A really messes things up -.-

          "AZ  -- string literal: "AZ"
         …     -- fill gaps: "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     S         -- with alphabet and
        ḣ      -- | alphabet rangified: ["A","AB","ABC",…,"AB……XYZ"]
      zJ       -- : zipWith join: ["A","ABB","ACBCC","ADBDCDD",…,"AZB……ZYZZ"]
Γ              -- pattern match (x:xs) with the following function (x is "A" and xs ["ABB","ACBCC",…,"A……ZYZZ"]
 · mh          -- | drop the last element of each element of xs: ["AB","ACBC",…,"A……ZYZ"]
  :            -- | cons (construct list): ["A","AB","ACBC",…,"A……ZYZ"]
               -- : strings are printed implicitly

Answer 6

Java 8, 121 bytes

I know there are better approaches but wanted to try it :)

q->{String s="";for(int i=0;i<26;i++){for(int j=0;j<((i<1)?1:i*2);j++){s+=(char)((j%2!=0?i:j/2)+65);}s+="\n";}return s;}

ungolfed:

static String d(){
    String s="";
    for(int i=0;i<26;i++){      //Loop for each line
        for(int j=0;j<((i<1)?1:i*2);j++){ //Loop to create the "word"
            s+=(char)((j%2!=0?i:j/2)+65);
        }
        s+="\n";
    }
    return s;
}

Answer 7

Red, 130 122 bytes

prin"A"repeat n 26[b: copy/part"ABCDEFGHIJKLMNOPQRSTUVWXYZ"n
foreach d copy/part b back tail b[prin d prin last b]print""]

Try it online!

Answer 8

F# (.NET Core), 132 bytes

let x=['A'..'Z']|>Seq.map(fun c->(+)(['A'..'Z']|>Seq.take((int c)-65)|>Seq.map(fun s->string s)|>String.concat(string c))(string c))

Try it online!

A naive port of my C# answer

Answer 9

Perl 6, 51 bytes

.say for 'A',{join |('A'..'Z')[++$,^++$ ],''}.../Z/

Try it

Expanded:

.say     # print with trailing newline

  for    # each of the following

    # start the sequence
    'A',

    # code used to generate the rest of the sequence
    {
      join
        | # flatten arguments

        ( 'A' .. 'Z' )[  # Range of characters
          ++$,           # auto incrementing anon state var (value used to join)
          ^++$           # Range upto an incrementing anon
        ],
        ''               # an empty string so that the joiner is added to end
    }

    ...  # keep doing that until
    /Z/  # there is a "Z" in the value

Answer 10

uBASIC, 80 bytes

Anonymous function that takes no input and outputs to the console

0?"A":ForI=65To89:ForJ=65ToI:?Left$(Chr$(J),1)+Left$(Chr$(I+1),1);:NextJ:?:NextI

Try it online!

Answer 11

Visual Basic .NET (Mono), 134 bytes

Declared function that takes no input and outputs to the console

Module M
Sub Main
Dim S,I,J
S="A"
For I=65To 90
Console.WriteLine(S)
S=""
For J=65To I
S+=Chr(J)+Chr(I+1)
Next
Next
End Sub
End Module

Try it online!

Answer 12

MY-BASIC, 77 bytes

Anonymous function that takes no input and outputs to the console.

Print"A";
For I=65 To 89
For J=65 To I
Print Chr(J)+Chr(I+1)
Next
Print;
Next

Try it online!

Answer 13

Yabasic, 60 bytes

?"A"
For I=65To 89
For J=65To I?Chr$(J)+Chr$(I+1);Next
?Next

Try it online!

Answer 14

Kotlin, 76 bytes

{for(l in 'A'..'Z'){for(c in 'A'..l){print(c)
if(c+1<l)print(l)}
println()}}

Try it online!

Answer 15

Perl 5, 35 bytes

@a=A..$_,$"=pop@a,say"@a$_"for A..Z

Try it online!

I managed to get frustratingly close for 23 bytes, but the above is the shortest valid solution I've managed so far:

$,=$_,say A..$,for A..Z

Try it online!

Answer 16

05AB1E, 12 bytes

AuηćsvyS¤ý¨»

Try it online.

Explanation:

Au            # Push the uppercase alphabet
  η           # Pop and push its prefixes
   ć          # Extract the head; pop and push the remainder and head
    sv        # Loop `y` over each of the remainder prefixes:
      yS      #  Convert `y` to a list of characters
        ¤     #  Push it's last character (without popping)
         ý    #  Join the characters by this character
          ¨   #  Remove the last character of the string
           »  #  And join the entire stack by newlines
              # (after the loop, the result is output implicitly)

Answer 17

Vyxal j, 63 bits^v2, 7.875 bytes

n¦ƛṫv+∑∨

Try it Online!

Bitstring:

100001100010111101100111000011000110100000111001111001111010011

Explained

n¦ƛṫv+∑∨­⁡​‎‎⁡⁠⁡‏⁠‎⁡⁠⁢‏⁠‎⁡⁠⁣‏‏​⁡⁠⁡‌⁢​‎‎⁡⁠⁤‏⁠‎⁡⁠⁢⁡‏⁠‎⁡⁠⁢⁢‏‏​⁡⁠⁡‌⁣​‎‎⁡⁠⁢⁣‏‏​⁡⁠⁡‌⁤​‎‎⁡⁠⁢⁤‏‏​⁡⁠⁡‌­
n¦ƛ       # ‎⁡To the prefixes of the lowercase alphabet:
   ṫv+    # ‎⁢  Add the tail to each character in (the prefix with the tail removed).
      ∑   # ‎⁣  Convert to a single string
       ∨  # ‎⁤  Special case the first a
💎

Created with the help of Luminespire.

Answer 18

Julia 1.0, 40 bytes

!_=["A";'B':'Z'.|>i->join(('A':i-1).*i)]

Try it online!

function taking an unused argument and ouputing an array of strings

Answer 19

Zsh, 40 bytes

for c ({A..Z})<<<${(pj:$c:)s}$c&&s+=($c)

Try it online!

for c ({A..Z})             # for each character
    <<< ${(pj:$c:)s}$c &&  # print line
    #   ${(p     ) }       # - enable simple $parameters inside PE flags
    #   ${( j:$c:) }       # - join with $c
    #   ${        s}$c     # - concatenate $s with $c
    s+=($c)                # add $c to the end of the list $s

Answer 20

Clean, 74 72 bytes

import StdEnv
Start=("A",[(zip2['A'..s-one][s,s..],'
')\\s<-['A'..'Z']])

Try it online!

This actually doesn't print a String, but rather a bare (String, [([(Char, Char)], Char)]), which is functionally the same. Unless you grab the output from this with another Clean program.

Answer 21

C (gcc), 77 bytes

f(i,j){for(i=0;i<26;puts("A"+!!i++))for(j=0;j<i;)printf("%c%c",j+++65,i+65);}

Try it online!

Answer 22

VBA, 60 Bytes

Anonymous VBE immediate window that takes no input and outputs to the VBE immediate window

?"A":For i=65To 89:For j=65To i:?Chr(j)Chr(i+1);:Next:?:Next

Answer 23

QBasic 1.1, 62 bytes

Takes no input and outputs to the STDIN

?"A"
FOR i=65TO 89
FOR j=65TO i
?CHR$(j)CHR$(i+1);
NEXT
?
NEXT

Answer 24

Easyfuck, 36 bytes

\ùòGEPAí½xÑZG×í½x¹ZG˯ÝzSHYòGËPM<¿v␄␘6Å␀ÿ

^{due to lack of unicode representations for c1 control characters, they have been replaced by their superscripted abbreviations}

Decompressed:

.>>$<_[=<4+$>_[=<.+$>._]=+>$>.<<_]@AA[␊

Explanation:

.>>$<_[=<4+$>_[=<.+$>._]=+>$>.<<_]@AA[␊
.>>$<                                   print the initial A
     _[=                        _]      loop until 2nd cell is equal to 3rd
        <4+$>                           set first cell to A
             _[=      _]=               loop until 1st cell is equal to 2nd
                <.+$>.                  print 1st cell and increment it, then print 2nd
                         +>$>.<<        increment 2nd cell and print 4th
                                  @     return
                                   AA[␊ initializer data