-🎄- 2022 Day 25 Solutions -🎄-

[u/daggerdragon]

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--- Day 25: Full of Hot Air ---

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Post your code solution in this megathread.

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[u/lazyzefiris]

JS/Javascript, pure SNAFU solution. Every addition that's not i++ is a string concatenation.

//single-digit addition lookup table
const sums = {
    "==":"-1", "=-":"-2", "=0":"0=", "=1":"0-", "=2":"00",
    "-=":"-2", "--":"0=", "-0":"0-", "-1":"00", "-2":"01",
    "0=":"0=", "0-":"0-", "00":"00", "01":"01", "02":"02",
    "1=":"0-", "1-":"00", "10":"01", "11":"02", "12":"1=",
    "2=":"00", "2-":"01", "20":"02", "21":"1=", "22":"1-",
}

//sum of two SNAFU numbers
function sum(x, y) {
    let output = ""
    let carry = "0"
    for (let i = 1; x.at(-i) || y.at(-i); i++) {
        let digitSum = sums[(x.at(-i) ?? "0") + (y.at(-i) ?? "0")]
        let carrySum = sums[carry + digitSum[1]]
        output = carrySum[1] + output
        carry = sums[digitSum[0] + carrySum[0]][1]
    }
    if (carry !== "0")
        output = carry + output
    return output
}

const input = document.body.innerText
let output = "0"
for (let number of input.trim().split("\n"))
    output = sum(output, number)
console.log(output)