this post was submitted on 01 Dec 2023
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[–] [email protected] 4 points 11 months ago

Have been mostly using jq for fun.

Day 1

Part 1

#!/usr/bin/env jq -n -R -f

# Get and reduce every "pretty" line
reduce inputs as $line (
  0;
  # Add extracted number
  . + ( $line / "" | [ .[] | tonumber? ] | [first * 10 , last] | add )
)

First part was easy, and very suited to jq

Part 2

#!/usr/bin/env jq -n -R -f

# Define string to num value map
{
  "one":   1,  "1": 1,
  "two":   2,  "2": 2,
  "three": 3,  "3": 3,
  "four":  4,  "4": 4,
  "five":  5,  "5": 5,
  "six":   6,  "6": 6,
  "seven": 7,  "7": 7,
  "eight": 8,  "8": 8,
  "nine":  9,  "9": 9
} as $to_num |

# Get and reduce every "pretty" line
reduce inputs as $line (
  0;
  . + (
    $line |
    # Try two capture two numbers
    capture("(^.*?(?(one|two|three|four|five|six|seven|eight|nine|[1-9])).*(?(one|two|three|four|five|six|seven|eight|nine|[1-9])).*?$)?") |
    # If no capture, get one number twice
    if .f == "" then $line | capture("^.*?(?(one|two|three|four|five|six|seven|eight|nine|[1-9]))") | .l = .f else . end |
    # Add extracted number
    $to_num[.f] * 10 + $to_num[.l]
  )
)

Second part was harder than expected, i had to resort to regex.

Day 2

Part 1

#!/usr/bin/env jq -n -R -f

# For each game: Is 12 red cubes, 13 green cubes, and 14 blue cubes possible ?
# Line Format =
# Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
[
  # Splitting input game id and content
  inputs / ": " |
  # Saving id
  (.[0] / " " | .[1] | tonumber ) as $id |
  # Parsing game
  .[1] / "; " | [
    .[] / ", " | [ .[] / " " | {(.[1]): .[0] | tonumber} ] | add |
    # Is given sample possible ?
    .red <= 12 and .green <= 13 and .blue <= 14
  ] |
  # If all samples possible, return id, else 0
  if all then $id else 0 end
] |

# Return sum of all possible game ids
add

Not too much trickery in this example.

Part 2

#!/usr/bin/env jq -n -R -f

# Line Format =
# Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
[
  # Splitting input game id and content
  inputs / ": " |
  # Parsing game
  .[1] / "; " |
    [ .[] / ", " | [ .[] / " " | {(.[1]): .[0] | tonumber} ] | add ] |
    # Getting minimum required mumber for each color,
    # and computing the power
    {
      r: ([.[].red]   | max),
      g: ([.[].green] | max),
      b: ([.[].blue]  | max)
    } | .r * .g * .b
] |

# Return sum of all powers
add

Satisifyingly straightfoward edit form part one.

Day 3

Part 1

#!/usr/bin/env jq -n -R -f

# Getting input with padding, and padded width
[ "." + inputs + "." ] as $inputs | ( $inputs[0] | length ) as $w |

# Working with flattened string, convert all symbols to '#'
[
  ([range($w) | "."]|join("")), # Padding
  $inputs[],
  ([range($w) | "."]|join(""))  # Padding
] | join("") | gsub("[^0-9.]";"#") as $inputs |

reduce (
  # Get all indices for symbols, in box pattern around symbols
  $inputs | indices("#")[] |
  . - $w -1  , . - $w , . - $w + 1 ,
  . - 1      , empty  , . + 1      ,
  . + $w - 1 , . + $w , . + $w + 1
) as $i (
  # Numbers containes bounding indices,
  # of numbers bordering symbols
  {numbers: []};

  # Test if current index isn't included in any found number
  def new_number($i): [ .numbers[] | .[0] <= $i and $i <= .[1] ] | any | not ;
  # Make "number" as bounding indices, by extending left and right
  def make_number($i):
    {a: $i, b: ($i+1 )}
      | until( $inputs[.a:.b] | test("^[^0-9]"); .a -= 1 )
      | until( $inputs[.a:.b] | test("[^0-9]$"); .b += 1 )
      | [ .a +1 , .b -1 ]
  ;

  # Add numbers if bordering symbol and new
  if ($inputs[$i:$i+1] | test("[0-9]")) and new_number($i) then .numbers += [ make_number($i) ] else . end
) |

# Output sum of all found numbers
[ .numbers[] | $inputs[.[0]:.[1]] | tonumber ] | add

Took More time than i expected, glad i had the idea early to search by the indices of the symbols and not the digits. Not super well suited to jq, unless I'm missing a better solution.

Part 2

#!/usr/bin/env jq -n -R -f

# Getting input with padding, and padded width
[ "." + inputs + "." ] as $inputs | ( $inputs[0] | length ) as $w |

# Working with flattened string, only keep gear '*' symbols
[
  ([range($w) | "."]|join("")), # Padding
  $inputs[],
  ([range($w) | "."]|join(""))  # Padding
] | join("") | gsub("[^0-9*]";".") as $inputs |

# Iterate over index positions of all gears
reduce ($inputs | indices("*")[]) as $i (
  0;
  # Re-use part-1 functions
  def new_number($i):
    [ .numbers[] | .[0] <= $i and $i <= .[1] ] | any | not
  ;
  def make_number($i):
    {a: $i, b: ($i+1 )}
      | until( $inputs[.a:.b] | test("^[^0-9]"); .a -= 1 )
      | until( $inputs[.a:.b] | test("[^0-9]$"); .b += 1 )
      | [ .a +1 , .b -1 ]
  ;
  # Reset and add numbers for each "box" ids
  def add_numbers($box_idx):
    reduce $box_idx[] as $i ({numbers:[]};
      if ($inputs[$i:$i+1] | test("[0-9]")) and new_number($i) then
        .numbers += [ make_number($i) ]
      else
        .
      end
    )
  ;
  add_numbers([
    $i - $w -1 , $i - $w , $i -$w + 1 ,
    $i - 1     , empty   , $i + 1     ,
    $i + $w - 1, $i + $w , $i + $w + 1
  ]).numbers as $numbers |

  if $numbers | length == 2 then
    # Add product if exactly two bordering numbers
    . += ( $numbers | map($inputs[.[0]:.[1]]|tonumber) | .[0] * .[1] )
  else
    .
  end
)

Not too far of an edit from part one.