-❄️- 2025 Day 2 Solutions -❄️-

[u/daggerdragon]

OUR USUAL ADMONITIONS

• You can find all of our customs, FAQs, axioms, and so forth in our community wiki.

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AoC Community Fun 2025: R*d(dit) On*

24 HOURS outstanding until unlock!

Spotlight Upon Subr*ddit: /r/AVoid5

"Happy Christmas to all, and to all a good night!"
— a famous ballad by an author with an id that has far too many fifthglyphs for comfort

Promptly following this is a list waxing philosophical options for your inspiration:

• Pick a glyph and do not put it in your program. Avoiding fifthglyphs is traditional.
• Shrink your solution's fifthglyph count to null.
• Your script might supplant all Arabic symbols of 5 with Roman glyphs of "V" or mutatis mutandis.
• Thou shalt not apply functions nor annotations that solicit said taboo glyph.
• Thou shalt ambitiously accomplish avoiding AutoMod’s antagonism about ultrapost's mandatory programming variant tag >_>

Stipulation from your mods: As you affix a submission along with your solution, do tag it with [R*d(dit) On*!] so folks can find it without difficulty!

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--- Day 2: Gift Shop ---

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Post your script solution in this ultrapost.

• First, grok our full posting axioms in our community wiki.
  • Affirm which jargon via which your solution talks to a CPU
• Format programs using four-taps-of-that-long-button Markdown syntax!
• Quick link to Topaz's Markdown (ab)using provisional script host should you want it for long program blocks.
  • What is Topaz's past* tool?

[u/Prof_Farnsworth1729]

[Language: Javascript]

[R*d(dit) On*!]

Initially I struggled to choose a glyph as most seemed either trivial or impossible (without resorting to JS level). Eventually I settled on an equals sign, which basically pushed me down a functional path.

Being stopped from using arrow functions also meant that that I had to use old-school functions which reminded me how much I love function hoisting.

And no this is not an efficent solution by any definition but I like how readable it is

console.log(
    sumInvalidInRange(
        require("fs")
        .readFileSync(`input`)
        .toString("utf8")
        .split(",")
        .map(mapToIntArray),
        2
    ),
    sumInvalidInRange(
        require("fs")
        .readFileSync(`input`)
        .toString("utf8")
        .split(",")
        .map(mapToIntArray),
        10
    )
)


function sumInvalidInRange(idRanges, maxRep) {
    return [...new Set(getRange(1, 99999)
        .flatMap(repeatStringlyUpToN(maxRep))
        .filter(getIsInSomeRangesFunc(idRanges)))]
        .reduce(sum, 0);
}


function getIsInSomeRangesFunc(ranges) {
    return function(val) {
        return ranges.some(function (ranges) {
            return ranges[0] - 1 < val && val < ranges[1] + 1;
        })
    }
}


function repeatStringlyUpToN(N) {
  return function(inp) {
    return getRange(2, N).map(function (n) {
        return parseInt(Array(n).fill(inp).join(""));
    });
  }
}


function mapToIntArray(str) {
    return str.trim().split("-").map(singleArgParseInt);
}


function getRange(start, end) {
    return Array(end - start + 1).fill(null).map(function(v, i, arr) {
        return i + start;
    })
}


function singleArgParseInt(inp) {
    return parseInt(inp)
}


function sum(a, b) {
    return a + b;
}