While I do agree that math gets much easier with interest, and that it gets more interesting the further you get into it, and that math is inherently beautiful, etc. I feel this argument has to fall flat to people who don’t already agree. It’s the education equivalent of when someone says they couldn’t get into an anime and then the fans tell them ‘oh it gets really good around season 9’. You could be completely correct, as you are here, but it’s utterly unconvincing if you don’t already “know.”

To be fair, I think this is mostly a problem with math curricula. Math classes up through high school and early college seem to focus on well trodden solutions to boring problems, and at some (far too late) point it flips around to being creative solutions to interesting problems. I think this could be fixed eventually, but such is the system we have now.

Damn you, Sonic the Hedgehog!

I live in Washington state and I’m pretty certain the sales tax here is 10% (slightly higher than your maximum figure of 9.56%). It’s a pretty well known trick here that you can account for tax just by decimal shifting and adding (ex: 5.29$ without would be 5.29$ + 0.529$ ~= 5.81$ with tax). Is that 9.56% an “in practice” figure that accounts for rounding down? I’m curious where you read it.

Uganda ain’t blue enough!

The thing that finally got businesses to finally get off IE wasn’t from the browser being worse than every other option. Heck, it wasn’t even because it was a decrepit piece of software that lost it’s former market dominance (and if anything businesses see that as a positive, not a negative).

What finally did that was microsoft saying there won’t be any security updates. That’s what finally got them off their ass; subtly threatening them with data breaches, exploits, etc. if they continue to use it. I don’t see google doing this anytime soon, at least not without a “sequel” like microsoft had with edge.

I have mine set up with a bunch of categories that are sorted with a prepended 3-digit number. Allows me to have different sections of category without it getting mixed up. ex:

010 S
011 A+
012 A
013 A-
014 B+
etc...
350 plz play soon
355 wont play
...
800 dont remember buying this

Odin

When I read the problem description I expected the input to also be 2 digit numbers. When I looked at it I just had to say “huh.”

Second part I think you definitely have to do in reverse (edit: if you are doing a linear search for the answer), as that allows you to nope out as soon as you find a match, whereas with doing it forward you have to keep checking just in case.

Formatted code

package day5

import "core:fmt"
import "core:strings"
import "core:slice"
import "core:strconv"

Range :: struct {
    dest: int,
    src: int,
    range: int,
}

Mapper :: struct {
    ranges: []Range,
}

parse_range :: proc(s: string) -> (ret: Range) {
    rest := s

    parseLen := -1

    destOk: bool
    ret.dest, destOk = strconv.parse_int(rest, 10, &parseLen)
    rest = strings.trim_left_space(rest[parseLen:])

    srcOk: bool
    ret.src, srcOk = strconv.parse_int(rest, 10, &parseLen)
    rest = strings.trim_left_space(rest[parseLen:])

    rangeOk: bool
    ret.range, rangeOk = strconv.parse_int(rest, 10, &parseLen)

    return
}

parse_mapper :: proc(ss: []string) -> (ret: Mapper) {
    ret.ranges = make([]Range, len(ss)-1)
    for s, i in ss[1:] {
        ret.ranges[i] = parse_range(s)
    }

    return
}

parse_mappers :: proc(ss: []string) -> []Mapper {
    mapsStr := make([dynamic][]string)
    defer delete(mapsStr)

    restOfLines := ss
    isLineEmpty :: proc(s: string)->bool {return len(s)==0}

    for i, found := slice.linear_search_proc(restOfLines, isLineEmpty); 
        found; 
        i, found  = slice.linear_search_proc(restOfLines, isLineEmpty) {
        
        append(&mapsStr, restOfLines[:i])
        restOfLines = restOfLines[i+1:]
    }
    append(&mapsStr, restOfLines[:])

    return slice.mapper(mapsStr[1:], parse_mapper)
}

apply_mapper :: proc(mapper: Mapper, num: int) -> int {
    for r in mapper.ranges {
        if num >= r.src && num - r.src < r.range do return num - r.src + r.dest
    }

    return num
}

p1 :: proc(input: []string) {
    maps := parse_mappers(input)
    defer {
        for m in maps do delete(m.ranges)
        delete(maps)
    }

    restSeeds := input[0][len("seeds: "):]
    min := 0x7fffffff

    for len(restSeeds) > 0 {
        seedLen := -1
        seed, seedOk := strconv.parse_int(restSeeds, 10, &seedLen)
        restSeeds = strings.trim_left_space(restSeeds[seedLen:])

        fmt.print(seed)
        for m in maps {
            seed = apply_mapper(m, seed)
            fmt.print(" ->", seed)
        }
        fmt.println()

        if seed < min do min = seed
    }

    fmt.println(min)
}

apply_mapper_reverse :: proc(mapper: Mapper, num: int) -> int {
    for r in mapper.ranges {
        if num >= r.dest && num - r.dest < r.range do return num - r.dest + r.src
    }

    return num
}

p2 :: proc(input: []string) {
    SeedRange :: struct {
        start: int,
        len: int,
    }

    seeds := make([dynamic]SeedRange)
    restSeeds := input[0][len("seeds: "):]

    for len(restSeeds) > 0 {
        seedLen := -1
        seedS, seedSOk := strconv.parse_int(restSeeds, 10, &seedLen)
        restSeeds = strings.trim_left_space(restSeeds[seedLen:])

        seedL, seedLOk := strconv.parse_int(restSeeds, 10, &seedLen)
        restSeeds = strings.trim_left_space(restSeeds[seedLen:])

        append(&seeds, SeedRange{seedS, seedL})
    }

    maps := parse_mappers(input)
    defer {
        for m in maps do delete(m.ranges)
        delete(maps)
    }

    for i := 0; true; i += 1 {
        rseed := i
        #reverse for m in maps {
            rseed = apply_mapper_reverse(m, rseed)
        }

        found := false
        for sr in seeds {
            if rseed >= sr.start && rseed < sr.start + sr.len {
                found = true
                break
            }
        }
        if found {
            fmt.println(i)
            break
        }
    }
}

Oh yeah, I misspoke, gonna edit.

hmm, my code keeps getting truncated at for y in .., anyone have any idea why? Maybe the “<” right after that confuses a parser somewhere?

Did this in Odin

Here’s a tip: if you are using a language / standard library that doesn’t have a set, you can mimic it with a map from your key to a nullary (in this case an empty struct)

formatted code

package day3

import "core:fmt"
import "core:strings"
import "core:unicode"
import "core:strconv"

flood_get_num :: proc(s: string, i: int) -> (parsed: int, pos: int) {
    if !unicode.is_digit(rune(s[i])) do return -99999, -1

    pos = strings.last_index_proc(s[:i+1], proc(r:rune)->bool{return !unicode.is_digit(r)})
    pos += 1

    ok: bool
    parsed, ok = strconv.parse_int(s[pos:])

    return parsed, pos
}

p1 :: proc(input: []string) {
    // wow what a gnarly type
    foundNumSet := make(map[[2]int]struct{})
    defer delete(foundNumSet)

    total := 0

    for y in 0..

Did mine in Odin. Found this day’s to be super easy, most of the challenge was just parsing.

package day2

import "core:fmt"
import "core:strings"
import "core:strconv"
import "core:unicode"

Round :: struct {
    red: int,
    green: int,
    blue: int,
}

parse_round :: proc(s: string) -> Round {
    ret: Round

    rest := s
    for {
        nextNumAt := strings.index_proc(rest, unicode.is_digit)
        if nextNumAt == -1 do break
        rest = rest[nextNumAt:]

        numlen: int
        num, ok := strconv.parse_int(rest, 10, &numlen)
        rest = rest[numlen+len(" "):]

        if rest[:3] == "red" {
            ret.red = num
        } else if rest[:4] == "blue" {
            ret.blue = num
        } else if rest[:5] == "green" {
            ret.green = num
        }
    }

    return ret
}

Game :: struct {
    id: int,
    rounds: [dynamic]Round,
}

parse_game :: proc(s: string) -> Game {
    ret: Game

    rest := s[len("Game "):]

    idOk: bool
    idLen: int
    ret.id, idOk = strconv.parse_int(rest, 10, &idLen)
    rest = rest[idLen+len(": "):]

    for len(rest) > 0 {
        endOfRound := strings.index_rune(rest, ';')
        if endOfRound == -1 do endOfRound = len(rest)

        append(&ret.rounds, parse_round(rest[:endOfRound]))
        rest = rest[min(endOfRound+1, len(rest)):]
    }

    return ret
}

is_game_possible :: proc(game: Game) -> bool {
    for round in game.rounds {
        if round.red   > 12 ||
           round.green > 13 ||
           round.blue  > 14 {
            return false
        }
    }
    return true
}

p1 :: proc(input: []string) {
    totalIds := 0

    for line in input {
        game := parse_game(line)
        defer delete(game.rounds)

        if is_game_possible(game) do totalIds += game.id
    }

    fmt.println(totalIds)
}

p2 :: proc(input: []string) {
    totalPower := 0

    for line in input {
        game := parse_game(line)
        defer delete(game.rounds)

        minRed   := 0
        minGreen := 0
        minBlue  := 0
        for round in game.rounds {
            minRed   = max(minRed  , round.red  )
            minGreen = max(minGreen, round.green)
            minBlue  = max(minBlue , round.blue )
        }

        totalPower += minRed * minGreen * minBlue
    }

    fmt.println(totalPower)
}

Did this in Odin (very hashed together, especially finding the last number in part 2):

package day1

import "core:fmt"
import "core:strings"
import "core:strconv"
import "core:unicode"

p1 :: proc(input: []string) {
    total := 0

    for line in input {
        firstNum := line[strings.index_proc(line, unicode.is_digit):][:1]
        lastNum := line[strings.last_index_proc(line, unicode.is_digit):][:1]

        calibrationValue := strings.concatenate({firstNum, lastNum})
        defer delete(calibrationValue)

        num, ok := strconv.parse_int(calibrationValue)

        total += num
    }

    // daggonit thought it was the whole numbers
    /*
    for line in input {
        firstNum := line

        fFrom := strings.index_proc(firstNum, unicode.is_digit)
        firstNum = firstNum[fFrom:]

        fTo := strings.index_proc(firstNum, proc(r:rune)->bool {return !unicode.is_digit(r)})
        if fTo == -1 do fTo = len(firstNum)
        firstNum = firstNum[:fTo]


        lastNum := line
        lastNum = lastNum[:strings.last_index_proc(lastNum, unicode.is_digit)+1]
        lastNum = lastNum[strings.last_index_proc(lastNum, proc(r:rune)->bool {return !unicode.is_digit(r)})+1:]

        calibrationValue := strings.concatenate({firstNum, lastNum})
        defer delete(calibrationValue)

        num, ok := strconv.parse_int(calibrationValue, 10)
        if !ok {
            fmt.eprintf("%s could not be parsed from %s", calibrationValue, line)
            return
        }

        total += num;
    }
    */

    fmt.println(total)
}

p2 :: proc(input: []string) {
    parse_wordable :: proc(s: string) -> int {
        if len(s) == 1 {
            num, ok := strconv.parse_int(s)
            return num
        } else do switch s {
            case "one"  : return 1
            case "two"  : return 2
            case "three": return 3
            case "four" : return 4
            case "five" : return 5
            case "six"  : return 6
            case "seven": return 7
            case "eight": return 8
            case "nine" : return 9
        }

        return -1
    }

    total := 0

    for line in input {
        firstNumI, firstNumW := strings.index_multi(line, {
            "one"  , "1",
            "two"  , "2",
            "three", "3",
            "four" , "4",
            "five" , "5",
            "six"  , "6",
            "seven", "7",
            "eight", "8",
            "nine" , "9",
        })
        firstNum := line[firstNumI:][:firstNumW]


        // last_index_multi doesn't seem to exist, doing this as backup
        lastNumI, lastNumW := -1, -1
        for {
            nLastNumI, nLastNumW := strings.index_multi(line[lastNumI+1:], {
                "one"  , "1",
                "two"  , "2",
                "three", "3",
                "four" , "4",
                "five" , "5",
                "six"  , "6",
                "seven", "7",
                "eight", "8",
                "nine" , "9",
            })

            if nLastNumI == -1 do break

            lastNumI += nLastNumI+1
            lastNumW  = nLastNumW
        }
        lastNum := line[lastNumI:][:lastNumW]

        total += parse_wordable(firstNum)*10 + parse_wordable(lastNum)
    }

    fmt.println(total)
}

Had a ton of trouble with part 1 until I realized I misinterpreted it. Especially annoying because the example was working fine. So paradoxically part 2 was easier than 1.

It’s a setting you can change. The default is a “quick generation” mode which looks as similar to the world seed/settings as it can without taking the performance hit of actually generating it. But it can either be changed to generate the chunks genuinely out to the render distance (which would be lag hell for 128 chunks) or to only render already generated chunks (like you suspect). Only the latter works in multiplayer though.