Alphabet Staircase

Question

The Challenge

Your task is to create a program or function that outputs the following with no input:

a
bb
ccc
dddd
eeeee
ffffff
ggggggg
hhhhhhhh
iiiiiiiii
jjjjjjjjjj
kkkkkkkkkkk
llllllllllll
mmmmmmmmmmmmm
nnnnnnnnnnnnnn
ooooooooooooooo
pppppppppppppppp
qqqqqqqqqqqqqqqqq
rrrrrrrrrrrrrrrrrr
sssssssssssssssssss
tttttttttttttttttttt
uuuuuuuuuuuuuuuuuuuuu
vvvvvvvvvvvvvvvvvvvvvv
wwwwwwwwwwwwwwwwwwwwwww
xxxxxxxxxxxxxxxxxxxxxxxx
yyyyyyyyyyyyyyyyyyyyyyyyy
zzzzzzzzzzzzzzzzzzzzzzzzzz

Scoring

This is code-golf, so the shortest answer in each language wins.

Answer 1

05AB1E, 2 bytes

Aƶ

Try it online!

Note that this outputs as a list of lines, as the OP explicitly allowed. The link uses a version with pretty-print (joined by newlines).

How it works

• A yields the lowercase alphabet.
• ƶ lifts the alphabet (multiplies each element by its index).
• » joins by newlines.

Answer 2

Python 2, 36 bytes

i=1
exec'print chr(i+96)*i;i+=1;'*26

Try it online!

Answer 3

APL (Dyalog), 12 8 5 bytes ^SBCS

3 bytes saved thanks to @ngn

4 bytes saved thanks to @Adám

⍴⍨⌸⎕A

OP clarified uppercase letters are valid, as well as output as an array of strings.

Try it online!

How?

⌸ gives us every letter in the ⎕A lphabet with its indexes in it, handed into the function ⍴⍨ with the letter as left argument and the indexes as right argument.

⍴⍨ resha ⍴ es its right argument to the length supplied by its left one. ⍨ switches the left and right (therefore the symbol of it, looking like the face of someone reading this explanation).

Answer 4

Haskell, 27 bytes

[c<$['a'..c]|c<-['a'..'z']]

Try it online! Returns a list of lines. (Thanks to @totallyhuman for pointing out that this is now allowed)

Explanation:

             c<-['a'..'z']  -- for each character c from 'a' to 'z'
[           |c<-['a'..'z']] -- build the list of
[   ['a'..c]|c<-['a'..'z']] -- the lists from 'a' to c, e.g. "abcd" for c='d'
[c<$['a'..c]|c<-['a'..'z']] -- with each element replaced by c itself, e.g. "dddd"

Answer 5

brainfuck, 74 bytes

++++++++[>+>+++>++++++++++++<<<-]>++>++>+>+<<[->>[->+<<.>]>[-<+>]<+<+<<.>]

Try it online!

Explanation

++++++++[>+>+++>++++++++++++<<<-]>++>++>+>+
TAPE:
  000
  010   C_NEWLINE
  026   V_ITERCOUNT
  097   V_ALPHA
 >001<  V_PRINTCOUNT
  000   T_PRINTCOUNT

V_ITERCOUNT TIMES:      <<[-   

  V_PRINTCOUNT TIMES:     >>[-
    INC T_PRINTCOUNT        >+
    OUTPUT V_ALPHA          <<.
                          >]

  RESTORE V_PRINTCOUNT    >[-<+>]
  INC V_PRINTCOUNT        <+
  INC V_ALPHA             <+
  OUTPUT C_NEWLINE        <<.
                        >]

Try it online!

Answer 6

Befunge-98 (FBBI), 27 bytes

1+:0\::'`j'@+\k:$$>:#,_$a,

where is a substitution character (ASCII 26)

Try it online!

Uses uppercase letters, and has a trailing newline.

Explanation

The code works by storing a counter (0 initially), and on every loop:

• 1+ - Increments it by 1
• :0\:: - Pushes things so that the stack looks like this: bottom [N, 0, N, N, N] top
• '`j'@ - Checks if the counter is greater than 26
  • j'@ - If it is, we jump over the ' and exit using @
  • j'@ - If it isn't, we execute the ', which pushes the ASCII value of @ to the stack

Now the stack looks like this: bottom [N, 0, N, N, 64] top

• +\ - Adds, then switches the top 2: bottom [N, 0, (N+64), N] top The first time through, this is ASCII 65, or A
• k: - Duplicates the second from the top (N+1) times - now there are (N+2) values of (N+64) on the stack (plus the N and 0 from earlier)
• $$ - Throw away the top 2 values - now there are only N values of (N+64)
• >:#,_ - Prints each top value until it gets to a 0 - this means N copies of (N+64) get printed
• $ - Throws away the 0 - Now the stack is just N
• a, - Prints an enter

And it repeats

---

I like how I used the @ both for ending the program and for adding to the counter.

Answer 7

Ruby, 32 30 bytes

-2 bytes thanks to @EricDuminil.

27.times{|n|puts (n+96).chr*n}

Try it online!

Answer 8

JavaScript (ES6), 54 bytes

f=(n=9)=>++n<36?n.toString(36).repeat(n-9)+`
`+f(n):''

O.innerText = f()

<pre id=O></pre>

Answer 9

Excel VBA, 38 bytes

Using Immediate Window. :)

[A1:A26]="=REPT(CHAR(96+ROW()),ROW())"

Answer 10

Ruby, 38 bytes

Returns an Array of strings

->{(a=*?a..?z).map{|x|x*-~a.index(x)}}

-5 bytes thanks to totallyhuman

*-11 bytes thanks to some excellent golfing by Jordan.

Answer 11

BASH, 59 54 40 bytes

for l in {a..z};{
a+=a
echo ${a//a/$l}
}

Try it online!

thx. 5 bytes to @Justin Mariner

Answer 12

V, 9 bytes

¬az\ÓÎÛäl

Try it online!

Hexdump:

00000000: ac61 7a5c d3ce dbe4 6c                   .az\....l

Answer 13

MATL, 9 bytes

2Y2"@X@Y"

Try it online!

Explanation

2Y2     % Push string 'abc...z'
"       % For char in that string each
  @     %   Push current char
  X@    %   Push iteration index (1-based)
  Y"    %   Run-length decoding: repeat char that many times
        % Implicit end. Implicit display

Answer 14

Jelly,  5  4 bytes

^{sneaky Python implementation abuse}

-1 byte thanks to Adám (outputting a list of lines has been allowed; as, now, has writing a function rather than a program)

Øa×J

A niladic link that returns a list of strings, the lines
(to print it with the newlines as a full program just add Y back in).

Try it online! (the footer calls the link as a nilad (¢) and gets the Python representation of the result (ŒṘ) for clarity as the default full-program behaviour would smash the result together like abbccc...)

How?

Øa×J - main link: no arguments
Øa   - yield the alphabet = ['a','b','c',...,'z']
   J - range of length    = [1,2,3,...,26]
  ×  - multiplication     = ["a","bb","ccc",...,"zzzzzzzzzzzzzzzzzzzzzzzzzz"]
     - (Python multiplication lengthens chars to strings - not usually a Jelly thing)

Answer 15

Japt, 9 7 bytes

Outputs an array of lines

;C¬Ëp°E

Try it

---

Explanation

Split (¬) the lowercase alphabet (;C) to an array of characters, map over the array (Ë) and repeat (p) the current element by the current index (E) incremented (°) times.

Answer 16

Python 3, 37 bytes

for k in range(27):print(chr(k+96)*k)

Prints a leading newline (which is allowed).

Try it online!

Answer 17

Javascript, 87 bytes, 72 bytes (A lot of thank to @steenbergh)

My first answer too:

for(i=1,j=97;j<123;){console.log(String.fromCharCode(j++).repeat(i++))};

Answer 18

MATL, 11 bytes

2Y2t!g*!YRc

Try it online!

Uses broadcast multiplication with ones to get a big square 26x26 matrix of the desired letters. Next, the lower triangular part is taken, and implicitly printed.

Also 11 bytes:

2Y2!t~!+YRc  % Using broadcast addition with zeroes
2Y2!l26X"YR  % Using 'repmat'

Answer 19

Perl 6,  24  23 bytes

.say for 'a'..'z'Zx 1..*

Try it

.say for 'a'..*Zx 1..26

Try it

Answer 20

Haskell, 31 bytes

-12 bytes thanks to nimi.

zipWith replicate[1..26]['a'..]

Try it online!

This is not a snippet, it is a nullary function (one that takes no arguments) that outputs a list of lines which is allowed because of this meta consensus.

Answer 21

Pip, 9 bytes

FczPcX++i

Try it online!

In pseudocode, this is

For-each c in z
    Print (c string-multiply ++i)

where z is preset to the lowercase alphabet and i is preset to 0.

---

Map-based solutions take one extra byte because they need the -n flag to display on multiple lines:

{aX++i}Mz
B X_+1MEz

Answer 22

Acc!!, 66 bytes

Count i while 26-i {
Count j while i+1-j {
Write 97+i
}
Write 10
}

Try it online!

With comments

# Loop i from 0 to 25
Count i while 26-i {
    # Loop j from 0 to i (inclusive)
    Count j while i+1-j {
        # Print a letter
        Write 97+i
    }
    # Print a newline
    Write 10
}

Answer 23

R, 38 bytes

A relatively uninteresting answer. Iterate for i from 1 to 26, print the ith letter of the alphabet i times (with an implicit line break).

for(i in 1:26)print(rep(letters[i],i))

Try it online!

A more interesting approach might be to use something like the following:

cat(letters[(1:351*2)^.5+.5])

This gives us all the letters in the right amount, but no linebreaks. Perhaps someone smarter than me can figure out a way to use that to make a golfier answer.

Answer 24

PHP, 47 46 bytes

for($c=a;$i<26;)echo"
",str_pad($c,++$i,$c++);

or

for($c=a;$i<26;)echo str_pad("
",++$i+1,$c++);

Run with -nr or try it online.

Answer 25

Perl 5, 19 bytes

say$_ x++$"for a..z

Try it online!

Answer 26

J, 18 17 bytes

a.{~(#"0+&96)i.27

Explanation:

              i.27      - list of integers 0 - 26
     (   +&96)          - adds 96 to the above list (starting offset of 'a')
      #"0               - copies the right argument left argument times  
  {~                    - select items from a list (arguments reversed)
a.                      - the whole alphabet


#"0 +&96 is a hook, which means that at first +96 is applied to the list i.27,
resulting in a list 96, 97, 98... 122, then #"0 is applied to this result. 
So it is evaluated as ((i.27)#"0(96+i.27)){a:

Try it online!

Answer 27

Rust, 82 bytes

||for i in 1..27u8{println!("{}",((i+96) as char).to_string().repeat(i as usize))}

I had hoped that it would've been a lot shorter, but explicitly converting/casting between types takes a lot of bytes :(

Try it online!

Answer 28

Octave, 25 24 bytes

['',tril((x=65:90)'+~x)]

Try it online!

Saved one byte thanks to Giuseppe who informed me that OP allows upper case letters.

Explanation:

Create a vector x with the ASCII-values of the upper case alphabet, and transpose it. Add the negated x (thus 26 zeros, in a row vector, in order to create a grid with (the ASCII-values of):

AAAA
BBBB
CCCC

Take the lower triangular matrix and convert to characters by concatenating with the empty string.

Answer 29

C (gcc), 48 bytes 50 bytes

Re-runnable version, as per cleblanc and Steadybox in the comments below.

s[9];main(i){for(;i<27;)puts(memset(s,i+95,i++));}

Try it online!

Answer 30

Japt, 17 16 11 bytes

_{-5 bytes thanks to Oliver}

In ISO-8859-1

;26ÆCgX pXÄ

Not the best score, but I'm still a novice. Any suggestions are very welcome.

Outputs list of lines, as OP allowed. Link contains 3 bytes more for newlines.

Try it online!

;                      - Use string variables
 26                    - Literal 26
   Æ                   - For range 0..26
    C                  - Alphabet
     gX                -         . character at index X
        pXÄ            - Duplicate X+1 times
                       - End function (implicit)

Answer 31

Brain-Flak, 107 bytes

((((()()()){}){}()){}){(({})){({}<(({})<({}((((()()()()){}){}){}){})>)>[()])}{}({}<((()()()()()){})>[()])}

Try it online!

This is 106 bytes of code, and +1 byte for the -A flag, which enables ASCII output.

Explanation:

#Push 26
((((()()()){}){}()){})

#While True...
{

    #Duplicate A
    (({}))

    #While True...
    {
        #Grab the value of A...
        ({}<

            #Make a duplicate of B (on the first loop, B == A)
            (({})<

                #Push B + 
                ({}

                #64 (ASCII 'A' - 1)
                ((((()()()()){}){}){}){})

            #Then push B on top of all of that
            >)

        #Push A - 1 on top of all of that
        >[()])

    #Endwhile, pop the loop counter
    }{}

    #Underneath A,
    ({}<

        #Push 10
        ((()()()()()){})

    # Then Push A - 1
    >[()])

#Endwhile
}

Answer 32

Brainfuck, 107 104 94 Bytes

>>>>++[<<<+++++++++++++>>++++[<++++++++>-]>>+++++<-]<<+>+[<]>[>>[<.>>+<-]>>.<<<+>+>[<+>-]<<<-]

How it works:

>>>>++[<<<+++++++++++++>>++++[<++++++++>-]>>+++++<-]<<+>+

Stores 26 on the second cell, 65 on the third cell, 10 on the sixth cell, and 1 on the fourth, leaving the pointer on the fourth (Saved 3 13 bytes by making 26, 10, and 97 65 at the same time).

[<]>

Moves the pointer back to the start.

Now we're ready to get started!

[                       | While the first cell is non-zero (so 26 times)
>>                      | Move to cell 3
    [                   | While cell 3 is non-zero
        <.>>+<-         | Print cell 2, increment cell 4, and decrement cell 3
    ]                   |
    >>.<<               | Move to cell 5 and print it (new line), then return
    <+>+>               | Increment cells 2 and 3, and move to 4
    [<+>-]              | Add the value at 4 to 3
<<<-                    | Decrement cell 1
]                       |

The important part is that cell 3 stores the number of times to print a letter. Each time a letter is printed, the value at 3 is moved to 4 and increased by 1, so that the next number is printed one more time than the last.

Side Note:

I'm completely new to brainfuck, so I wouldn't be surprised if this could be improved. However, I was also surprised by how fun brainfuck is to write, as well as by how easy it was to write, when compared with what I had imagined.

I would definitely recommend learning brainfuck to any bored programmers out there ;)

Answer 33

Pyke, 5 bytes

G Foh*

Try it here!

       - o=0
G      -  alphabet
  F    - for i in ^:
     * -  ^ * v
   oh  -   (o++)+1

Answer 34

Jelly, 7 6 bytes

ØaxJŒg

Try it online!

Returns a list of lines

How it works

ØaxJŒg - Main link. No arguments
Øa     - Lower case alphabet
  x    - each repeated...
   J   - range(len) times (vectorises)
    Œg - group equal runs

An alternative (which I prefer, but is longer):

ØaḊLСUZYṚ

Try it online!

Answer 35

Befunge, 37 35 bytes

:"a"+:>,#:\:#->#1_55+,$"`"-:55*`#@_

Try it online!

Explanation

The program starts with an implicit zero on the stack, representing the repeat count (off by 1).

:"a"+                                Duplicate the count and convert it to a character.
     :                               Duplicate the character prior to writing it out.

      >                              Start the output loop.
       ,                             Write the duped character to stdout.
          \                          Swap the count to the top of the stack.
           :  >  _                   Duplicate it and check if zero, returning left if not.
             -  1                    Decrement the count.
          \                          Swap the character back to the top.
         :                           Duplicate it prior to writing it out again.
      >                              Repeat the loop.

                 _                   If the count reached zero, we continue right.
                  55+,               Output a linefeed.
                      $              Drop the zero count.
                       "`"-          Convert the character to a numeric count and increment.
                           :55*`     Check if greater than 25.
                                #@_  If so, then terminate, else wrap back to the start.

Answer 36

VBA, 33 Bytes

Anonymous VBE immediate window function that outputs to the VBE immediate window

For i=1To 26:?String(i,96+i):Next

Answer 37

Java (OpenJDK 8), 74 bytes

n->{for(int i=1,j=0;i<27;)System.out.printf("%c",j++<i?96+i:10+(j-=++i));}

Try it online!

6 bytes saved thanks to @KevinCruijssen

Explanations

n->{                      // Lambda, unused parameter
 for(int i=1,j=0;i<27;)   // Loop from 1 to 26 included
  System.out.printf("%c", // Print a character
   j++<i                  // Do we need to print a letter or a new line?
    ?96+i                 // It's a character, construct it.
    :10+(j-=++i)          // It's a new line, increment i and reset j to 0.
  );
}

Answer 38

C# (.NET Core), 78 bytes

n=>{var s="";for(int i=1;i<27;)s+=new string((char)(i+96),i++)+'\n';return s;}

Try it online!

Answer 39

Mathematica, 33 bytes

Alphabet[][[#]]~Table~#&~Array~26

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Answer 40

Stacked, 14 bytes

[26~>:96+chr*]

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Pushes a list of lines to the stack.

Explanation

[26~>:96+chr*]
[            ]  anonymous function, takes no arguments
 26~>           range from 1 to 26
     :96+       push range from 97 to 122 (97..122')
         chr    convert each of these to a char ('a'..'z')
            *   repeat each char by the former amount ('a' 'bb' 'ccc' ...)

Answer 41

C (gcc), 53 bytes

i,j;f(){i=i-putchar(j++-i?96+i:(j=!++i)+10)-16&&f();}

Prints a leading newline. Has undefined behaviour, but works with gcc...

Try it online!

C, 54 bytes

j;main(i){for(;i<27;)putchar(j++-i?96+i:(j=!++i)+10);}

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C, 54 bytes

i,j;f(){putchar(j++-i?96+i:(j=!++i)+10);(i%=27)&&f();}

Prints a leading newline.

Try it online!

C, 56 bytes

main(i,j){for(;i<27;)for(j=++i;j--;)putchar(j?95+i:10);}

Try it online!

Answer 42

Charcoal, 6 bytes

Ｅβ×ι⊕κ

Try it online! Link is to verbose version of code. Explanation:

     κ  Index
    ⊕   Incremented
   ι    Character
  ×     Repeated
 β      Lowercase letters
Ｅ       Map over each character
        Implicitly print each result on its own line

Answer 43

Japt, 9 bytes

;C£RiXpYÄ

Try it online!

Answer 44

Retina, 20 bytes

:`
a
{2`
$`
T:`_l`l_

Try it online!

Prints a couple of trailing linefeeds.

Explanation

:`
a

Initialise the string to a and print it.

{2`
$`

The { tells Retina to loop the remainder of the program until it fails to change the string. The stage itself duplicates the first character.

T:`_l`l_

This increments all letters using transliteration and prints the result.

Answer 45

Brachylog, 7 bytes

Ại₁j₎ẉ⊥

Try it online!

Explanation

Ạ         The alphabet string "abcdefghijklmnopqrstuvwxyz"
 i₁       A couple: [a letter of the alphabet, its index (1-indexed) in it]
   j₎     Juxtapose that letter as many times as its index
     ẉ    Write followed by a linebreak
      ⊥   False: try another couple of [letter, index]

Answer 46

Elixir, 47 bytes

for x<-?a..?z,do: IO.puts List.duplicate x,x-96

Try it

Answer 47

JavaScript, 65 bytes

for(x=0;x<26;)console.log(String.fromCharCode(x+97).repeat(++x));

old:

for(x=0;x<26;x++)console.log((function p(a,b){return b==0?a:a+p(a,--b);})(String.fromCharCode(97+x),x));

Answer 48

Common Lisp, 65 bytes

(dotimes(a 26)(format t"~v@{~a~:*~}~%"(1+ a)(code-char(+ a 97))))

Try it online!

Answer 49

C# (.NET Core), 84 bytes

()=>{return A(1);string A(int n)=>new string((char)(n+96),n)+(n<26?"\n"+A(++n):"");}

Try it online!

A recursive approach using a local function (given no inputs were allowed).

UnGolfed

()=>{
    return A(1);
    string A(int n) => new string((char)(n+96), n) +
                       (n < 26? "\n" + A(++n) : "");
}

Answer 50

C# (.NET Core), 57 bytes

57 bytes with a a trailling line

()=>new int[27].Select((_,i)=>new string((char)(i+96),i))

59 bytes without a trailling line

()=>new int[26].Select((_,i)=>new string((char)(i+++97),i))

Try it online!

I am using using System.Linq;

• The int[x].Select() can be found here.

Answer 51

CJam, 13 bytes

26{)_96+c*N}%

Explanation:

26             e# push 26
  {        }%  e# for n in 0 .. 25:
   )           e#   increment
     96+       e#   add 96
        c      e#   convert to character
    _    *     e#   repeat that character n+1 times
          N    e#   add a newline

Answer 52

Underload, 62 bytes

()(::(.)~^(.):*:*:*:*:*::***( )*~^S(
)S(:)~*(*)*):*::*:*::***^

Try it online!

This is really stretching the limits of what's allowed.

It outputs a list of lines represented by strings (allowed by the OP), where the strings are lists of bytes (allowed by meta consensus), where the bytes are given in unary (also allowed by meta consensus).

The result is... well, see for yourself.

Answer 53

Kotlin, 56 bytes

for(c in 'a'..'z'){for(j in 0..c-'a')print(c);println()}

Try it online!

Answer 54

Befunge 2x24 = 48 Bytes

I know the other befunge answer has me solidly beat, but I thought I'd post my solution anyway, as it's interesting, since it's partially self-modifying.

"z`"-:!_> 10g\v v!:_0# p
g01+55$_^#!:-1<@_,1^01-1

Try It Online

How it works

"?`"-:!

Gets how many times to iterate. (The question mark represents the current letter)

        _> 10g\v
        _^#!:-1<

Adds the iteration size*char into the stack.

                   _0# p
g01+55$_           ^01-1 

Pops the excess character and adds a newline. Gets the current character from 1,0 and decrements it, putting back at 1,0

"?`"-:!_           _0# p

Now the ? inside the quotes has been decremented. Once it has run through all the letters it runs backwards from the underscore, which was the tricky part. ! inverts the excess 0 to a 1, which is duplicated and subtracted from itself, turning it back to a 0. The 0 is put at (97,97) thanks to the backticks inside the quotes and the put command. This leaves just the original iteration size, which is 0, when it hits the underscore, pushing the pointer left.

                v!:_
               @_,1^

Prints out the whole stack, which at this point is a newline separated alphabet staircase.

Answer 55

Kotlin, 37 bytes

{(1..26).map{"${'`'+it}".repeat(it)}}

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Returns a List of Strings

Answer 56

Pyth, 7 bytes

.e*hkbG

Try it online!

Outputs a list of lines. If that's not allowed, add a j to the start and let me know to add one byte to the count!

---

.e*hkbG  Full program - outputs to stdout
.e       map over
      G  the alphabet,
  *  b   repeating each letter
   hk    according to its index+1

Answer 57

JavaScript, 113 bytes

(function(){var i=0,j=0,s;while(++i<=26){s="";j=0;while(++j<=i)s+=String.fromCharCode(96+i);console.log(s);}})();

Answer 58

Tcl, 80 bytes

set a 97;time {time {puts -nonewline [format %c $a]} [incr i];puts "";incr a} 26

Try it online!

Answer 59

Funky, 42 bytes

fori=1i<27i++print("a".char(96+i)::rep(i))

Try it online!

Answer 60

C++, 56 bytes

for(char a='a';a<='z';++a)cout<<string(a-'a'+1,a)<<endl;

Try it online

Answer 61

QBIC, 23 bytes

[26|[a|?chr$(a+96)';`]?

Explanation

[26|   FOR a = 1 TO 26
[a|      FOR b = 1 TO a
?chr$(     PRINT the character
a+96)         a, or b, or c depending on outer loop
';`           and suppress new-lines, tabs etc
]          NEXT, for this character (a, bb, ccc)
?          PRINT a newline between a, bb, ccc....
       NEXT on outer loop added implicitly

Answer 62

K (oK), 16 bytes

Solution:

`c$t#'96+t:1_!27

Returns a list of lists. TIO prints to stdout:

Try it online!

Explanation:

`c$t#'96+t:1_!27 / the solution
             !27 / til 27, creates range of 0..26
           1_    / drop first element, 1..26 (could have done 1+!26 but 1_!26 is faster ;))
         t:      / store in variable v
      96+        / add 96 to each (97=a)
   t#'           / t take each, 1#97 = 97, 2#98 = 98 98, 3#99 = 99 99 99 etc
`c$              / cast to characters

Answer 63

PowerShell, 30 bytes

1..26|%{"$([char]($_+96))"*$_}

Try it online!

Also 30 bytes --

1..26|%{(""+[char]($_+96))*$_}

Try it online!

In either case, we're just looping 26 times, each iteration constructing a string of the appropriate character, then string-multiplying it out to the appropriate length. Ho-hum.

Answer 64

T-SQL, 68 bytes

Using a variable and loop:

DECLARE @ INT=1;a:PRINT REPLICATE(CHAR(@+96),@)SET @+=1IF @<27GOTO a

Longer (94 bytes), but feels much more SQL-like, using a recursive CTE to generate a number table:

WITH t AS(SELECT 1n UNION ALL SELECT n+1FROM t WHERE n<26)
SELECT REPLICATE(CHAR(n+96),n)FROM t

Answer 65

Check, 26 bytes

 >#v
#d##)::>96+]*o<:>26-?

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Explanation:

Check's gimmick is that it can switch between 2D semantics (for control flow) and 1D semantics (for stack manipulation). The program starts out at the beginning of the program in 1D semantics.

> pushes 0 to the stack. # switches to 2D semantics and v directs the IP downwards. It then hits #, switching back to 1D semantics for the main loop.

#d##)::>96+]*o<:>26-?

The commands before the ? go like this:

#    1D mode:                   0
)    increment:                 1
:    duplicate:                 1, 1
:    duplicate:                 1, 1, 1
>96  push 96:                   1, 1, 1, 96
+    add:                       1, 1, 97
]    wrap:                      1, 1, [97]
*    repeat:                    1, [97]
o    output char codes ("a"):   1
<    output newline ("\n"):     1
:    duplicate:                 1, 1
>26  push 26:                   1, 1, 26
-    subtract:                  1, -25

The ? is Check's only branching operator. It switches to 2D semantics if the TOS is nonzero, and stays in 1D semantics otherwise. In this case, if the top stack value is 0, then the program ends, and if it is negative, then it goes around to the beginning. # switches back to 1D semantics, d deletes the top stack element (since ? does not pop it). ## switches to 2D and then back again, and then the loop restarts.

Answer 66

Vim, 33 Keystrokes

:h<_␍jjYZZiyl0pr␛pqq{<C-a>YG@"q25@q{D

Explanation

:h<_␍jjYZZ                             " get a-z 
          iyl0pr                       " Put yl0pr as macro line 
                ␛p                     " Back to normal mode and paste
                  qq                   " Record macro
                    {                  " Go to macro line 
                     <C-a>             " Increment counter
                          Y            " Yank the macro
                           G           " Go to last line
                            @"         " Run the macro (also adds \r)
                              q        " Stop recording @q
                               25@q    " Run @q 25 times
                                   {D  " go to top and clear the line

Had experimented with this which inspired the above Macro line:

:h<_␍jjYZZP:exe ":norm yl".line('.')."ps^M"␍25@:

Thought about putting a-z on separate lines and global replace with repeat, but can't make :%s/./\=repeat(\0,line('.'))/g work -- and that's long.

Answer 67

brainfuck, 70 59 bytes

-<--[[<+>->----<]++>]<-<-<<[>>>[-<.>>+<]>[-<+>]<[+<]>->.->]

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-<--[[<+>->----<]++>]<-<-<<
Sets the tape up as:
     254
     9    Newline (10-1)
     230' Loop counter (-26)
     114  
     65   Character (A)
     1    Repeat counter
[ Loop 26 times
   >>>[-<.>>+<]   Print the character repeat counter times while preserving the counter
   >[-<+>]        Restore counter
   <[+<]          Increment everything
   >->.->         Print a newline
]

Answer 68

R, 33 bytes

cat(strrep(letters,1:26),sep="
")

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This challenge got bumped to main; I tried a strrep approach which was happily shorter than the other existing R answer.

Answer 69

Lua, 48 bytes

for i=1,26 do print(string.char(i+96):rep(i))end

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Explanation:

1. for i=1,26 do ... end — try all numbers between 1 and 26.
2. print(...) — prints, of couse.
3. string.char(i+96) — get alphabet char number i.
4. :rep(i) — repeat char i times.

Answer 70

Acc!!, 74 bytes

97
Count i while i-27 {
 	Count t while t-i {
 		Write _+i-1
	}
Write 10
}

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Answer 71

Wolfram Language (Mathematica), 43 bytes

This submission creates the specified output string exactly - in other words, it's NOT an array of string-enclosed characters.

#~Table~#2<>"\n"&~MapIndexed~Alphabet[]<>""

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Answer 72

Pushy, 8 bytes

Z26:q&Kh

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Z          \ Push 0 to the stack
 26:       \ 26 times do:
    q      \    Print stack, with each number as its letter in the 0-indexed lower alphabet
     &     \    Make a copy of the last number
      Kh   \    Increment all numbers

Answer 73

Kotlin, 76 bytes

for(i in 0..25){var j=0;while(j<=i){print((i+97).toChar());j++};print("\n")}

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Answer 74

C (gcc), 68 64 bytes

I know there's another C answer but this is a different approach

n=65;main(i){for(i=n;i-->64;putchar(n));++n>90||main(puts(""));}

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Answer 75

x86-64 machine code function, 19 bytes

18 bytes for x86-32 with a non-standard calling convention, inc eax is only 1B vs. 2B.

Callable from C (with the x86-64 System V calling convention) as:

void alphabet_staircase(char output[377]);

// or
struct string_result { char buf[377]; }  \
  alphabet_staircase(void);   // return-value pointer passed as implicit first arg

i.e. it stores a flat string (including '\n' newlines) into a buffer pointed to by rdi.

0000000000400080 <alphabet_staircase>:
  400080:       6a 61           push   0x61
  400082:       58              pop    rax      ; eax = 'a'

0000000000400083 <alphabet_staircase.loop>:
                                 ;;; do {
  400083:       8d 48 a1        lea    ecx,[rax-0x5f]      ; rax-'a'+1 + 1
  400086:       f3 aa           rep stos BYTE PTR es:[rdi],al
  400088:       c6 47 ff 0a     mov    BYTE PTR [rdi-0x1],0xa
  40008c:       ff c0           inc    eax
  40008e:       3c 7a           cmp    al,0x7a
  400090:       76 f1           jbe    400083 <alphabet_staircase.loop>
                                 ;;; } while(al <= 'z')
  400092:       c3              ret

  400093  end of function.  0x93 - 0x80 = 0x13 = 19 bytes

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In each loop iteration, we store one extra copy of current letter, then overwrite it with a newline. rep stosb = memset(rdi, al, rcx). It advances rdi to point one-past-the-end of the bytes it stored.

eax holds the current letter, and we use it as the loop counter. do {} while(eax <= 'z');. Setting rcx from it with LEA requires that the upper bytes of eax be zeroed, otherwise we could use 2-byte mov al, 'a' to start.

The x86-64 SysV ABI requires that DF is cleared on function entry/exit, so we don't need cld. If we wanted to use std to store backwards, it wouldn't solve the problem of needing an offset of one in an addressing mode to store the newline (or needing a separate inc/dec, or swapping eax with a reg holding 0x10 and using stosb to store a newline); stosb always overwrites the memory rdi is pointing to.

Answer 76

Ruby, 28 31 35 bytes

Edit: saved 3 bytes by using a number range instead of letters. Try it online!

(0..26).map{|l|(l+96).chr*l}

Edit: saved 4 bytes by using the character number instead of looping with index. Try it online!

('`'..'z').map{|l|l*(l.ord-96)}

Edit: saved 6 bytes by outputting a list. Try it online!

('`'..'z').map.with_index{|l,i|l*i}

Original:

('`'..'z').each_with_index{|l,i|puts l*i}

Answer 77

F# (.NET Core), 58 bytes

58 bytes

[1..26]|>Seq.map(fun i->new System.String((char)(i+96),i))

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A basic port of my C# answer.

59 bytes

[1..26]|>Seq.map(fun i->[1..i]|>Seq.map(fun _->i+96|>char))

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Same answer as above but without `System.String.

Answer 78

Javascript (ES6) 61 bytes

_=>[...Array(26)].map((_,i)=>(10+i).toString(36).repeat(i+1))

Javascript (ES6) 62 bytes

_=>[..."abcdefghijklmnopqrstuvwxyz"].map((v,i)=>v.repeat(i+1))

I'm aware there's a better answer already for js, still wanted to post these, feel free to suggest any improvement as long as it keeps the "methodology" intact. (for readability im using underscores for unused variables)

Answer 79

JsFuck, 7929c

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From

[].slice.call('trueundefinedundefinedtrue').filter([].filter.constructor('f=10\nreturn undefined=>console.log(f.toString(36).repeat(++f-10))')())

JsFuck, 7961c

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From

[].filter.constructor(unescape('returnfalse20ffalse3dfalse28tfalse3d10false29false3dfalse3etfalse2d36false3ftfalse2etfalse6ffalse53trinfalse67false2836false29false2erefalse70eatfalse28++tfalse2d10false29+false60false0afalse60+ffalse28tfalse29false3afalse22false22'.split(false).join('%')))

Both work on Firefox, because I only have it

Answer 80

SNOBOL4 (CSNOBOL4), 74 bytes

O	&LCASE POS(I) LEN(1) . X
	I =I + 1
	OUTPUT =LE(I,26) DUPL(X,I) :S(O)
END

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O	&LCASE POS(I) LEN(1) . X		;* set X to I'th 0-indexed character of lowercase letters
	I =I + 1				;* increment I
	OUTPUT =LE(I,26) DUPL(X,I) :S(O)	;* if I<=26, output X DUPLicated I times and goto O otherwise goto END
END

Answer 81

uBASIC, 57 bytes

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

0ForI=1To26:ForJ=1ToI:?Left$(Chr$(I+64),1);:NextJ:?:NextI

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Answer 82

MY-BASIC, 59 bytes

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

For I=1 To 26
For J=1 To I
Print Chr(I+64)
Next
Print;
Next

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Answer 83

Yabasic, 49 bytes

A BASIC answer that takes no input and outputs to the console.

For I=1To 26
For J=1To I
?Chr$(I+64);
Next
?
Next

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Answer 84

Visual Basic .NET (Mono), 120 bytes

Another BASIC answer

Module M
Sub Main
Dim S,I,J
For I=1To 26
S=""
For J=1To I
S+=Chr(I+64)
Next
Console.WriteLine(S)
Next
End Sub
End Module

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Answer 85

Pepe, 49 bytes

rEeEEeeeeEREeEEEEeEEREEreeereeErEEEeErEEEEEeeERee

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Explanation:

rEeEEeeeeE # Push A (r)
REeEEEEeEE # Push 91 (Z + 1) (R)
REE        # Start loop labeled 91
           # | All the following commands below operate on r
reee       # | Output whole stack of r
reeE       # | Output newline "\n"
rEEEeE     # | Duplicate char to end
rEEEEEeeE  # | Increment whole stack
Ree        # If r != 91, repeat loop

Answer 86

sed, 82 bytes

s:^:a:
:A
p
y:abcdefghijklmnopqrstuvwxy:bcdefghijklmnopqrstuvwxyz:
s:.:&&:
/z/q
bA

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Loop from a to z. The last line is printed implicitly, preceding lines are printed with a p.

Answer 87

MBASIC, 42 bytes

1 FOR I=1 TO 26:PRINT STRING$(I,96+I):NEXT

Answer 88

Whitespace, 127 bytes

Because the syntax is entirely in whitespace characters, each character is prefixed with S, T, or L (for Space, Tab, and Linefeed, respectively).

S S S T	L
L
S S L
S L
S S L
S S S S T	T	S S S S S L
T	S S S L
S S T	L
S L
S T	L
S S S L
T	S S S T	L
T	S S T	S L
S L
T	S T	S L
S L
T	L
S L
T	L
L
S S T	S L
S L
L
S L
L
S S S T	S T	S L
T	L
S S S S S T	L
T	S S S S L
S S S S T	T	S T	T	L
T	S S T	L
T	T	L
L
L
L

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Answer 89

Julia, 42 36 bytes

[println(l^(l-'`')) for l∈'a':'z']

Answer 90

K4, 13 bytes

(1+!26)#'.Q.a

Output:

q)k)(1+!26)#'.Q.a
,"a"
"bb"
"ccc"
"dddd"
"eeeee"
"ffffff"
"ggggggg"
"hhhhhhhh"
"iiiiiiiii"
"jjjjjjjjjj"
"kkkkkkkkkkk"
"llllllllllll"
"mmmmmmmmmmmmm"
"nnnnnnnnnnnnnn"
"ooooooooooooooo"
"pppppppppppppppp"
"qqqqqqqqqqqqqqqqq"
"rrrrrrrrrrrrrrrrrr"
"sssssssssssssssssss"
"tttttttttttttttttttt"
"uuuuuuuuuuuuuuuuuuuuu"
"vvvvvvvvvvvvvvvvvvvvvv"
"wwwwwwwwwwwwwwwwwwwwwww"
"xxxxxxxxxxxxxxxxxxxxxxxx"
"yyyyyyyyyyyyyyyyyyyyyyyyy"
"zzzzzzzzzzzzzzzzzzzzzzzzzz"

Answer 91

Scala (39 bytes)

('a'to'z')map(n=>println(s"$n"*(n-96)))

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Answer 92

Dart, 81 bytes

List.generate(26,(i)=>''.padRight(i+1,String.fromCharCode(i+97))).forEach(print);

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Answer 93

Ahead, 28 bytes

Featuring trailing newline!

'a'zEr~@~kdW<
~:\N\0<~'a-k:l

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