add README.md

Luckily M[30] is easily factorable as it is almost a perfect square.

Cargo.toml

@@ -6,10 +6,8 @@ edition = "2024"
 [dependencies]
 anyhow = "1.0.99"
 json = "0.12.4"
-lazy_static = "1.5.0"
 reqwest = { version = "0.12.23", features = ["blocking"] }
-rug = "1.28.0"
+rug = { version = "1.28.0", features = ["integer"], default-features = false }
-rand = "0.9.2"
 tqdm = "0.8.0"
 sha2 = "0.10.9"
 percent-encoding = "2.3.2"

README.md

@@ -0,0 +1,18 @@
+# button
+
+This repository contains code for solving the challenges from [button.qedaka.de](button.qedaka.de). There are eight
+challenges in total:
+- [01_welcome](./js/01_welcome.js)
+- [02_these_numbers_are_big](./js/02_these_numbers_are_big.js)
+- [03_are_you_still_doing_this_by_hand](./js/03_are_you_still_doing_this_by_hand.js)
+- [04_broken_proof_of_work](./js/04_broken_proof_of_work.js)
+- [05_what_the_bf](./js/05_what_the_bf.js)
+- [06_automation_is_not_enough](./js/06_automation_is_not_enough.js)
+- [07_weird_assembly_machine](./js/07_weird_assembly_machine.js)
+- [08_revisit_everything](./js/08_revisit_everything.js)
+
+Challenges one through four are trivial to solve. For challenges five through eight there is one binary each which
+demonstrates an approach to a solution.
+
+One additional binary for solving the whole puzzle from start to finish is provided.
+

src/bin/05_what_the_bf.rs

@@ -14,6 +14,7 @@ fn main() {
     println!("x = {x}");
 }
 
+/// Tries to find a cycle in [`f_n`] using Brent's algorithm.
 fn main_cycle_detection() {
     compute_async(|tx| {
         // brent's algorithm
@@ -69,20 +70,19 @@ fn main_cycle_detection() {
 }
 
 
-const A: u128 =   909_090_909_091u128; // (10 * b + 1) / 11
+/// The deobfuscated function `f`
-const B: u128 = 1_000_000_000_000u128; // 10^12
-const C: u128 =   999_999_999_989u128; // b - 11
-const D: u128 =   999_999_999_999u128; // b -  1
 fn f(mut x: u128) -> u128 {
+    const A: u128 =   909_090_909_091u128; // (10 * b + 1) / 11
+    const B: u128 = 1_000_000_000_000u128; // 10^12
+    const C: u128 =   999_999_999_989u128; // b - 11
+    const D: u128 =   999_999_999_999u128; // b -  1
+
     x = x * A % B;
     x = (x * C + D) / B;
     x
 }
 
-
+/// Computes `f(f(...f(X0)...))` (where [`f`] is applied `n` times) using data produces by [`main_cycle_detection`]
-const MU: u128 = 0;
-const LAM: u128 = 249_999_999_997;
-/// Computes `f(f(...f(X0)...))` where `f` is applied `n` times.
 fn f_n(n: u128) -> u128 {
     let n = n % LAM;
 
@@ -101,6 +101,13 @@ fn f_n(n: u128) -> u128 {
     value
 }
 
+/// The offset of the cycle of [`f_n`] as returned by [`main_cycle_detection`].
+const MU: u128 = 0;
+
+/// The length of the cycle of [`f_n`] as returned by [`main_cycle_detection`].
+const LAM: u128 = 249_999_999_997;
+
+/// In- and output values of [`f_n`] as returned by [`main_cycle_detection`].
 const F_DATA: &[(u128, u128)] = &[
     (11538000000, 540610237213),
     (11539000000, 525319061659),

src/bin/06_automation_is_not_enough.rs

@@ -3,38 +3,34 @@
 use anyhow::Result;
 use std::fs::File;
 use std::io::{BufRead, BufReader};
-use lazy_static::lazy_static;
 use rug::ops::MulFrom;
 use rug::{Assign, Integer};
 use std::ops::Add;
 use std::str::FromStr;
+use std::sync::LazyLock;
 use lib::submit;
 
-lazy_static!(
+static N0: LazyLock<Integer> = LazyLock::new(|| Integer::from(1001997000002u128));
-    static ref N0: Integer = Integer::from(1001997000002u128);
+static X0: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("13361120425250501347832030920224855036595311511513374827901659942687569213067904382419070310529480239935839308518100143939024253857202176158254361885679515473530816156355117821922648901555956036125537445852483998567339002752976575910942962150").unwrap());
-    static ref X0: Integer = Integer::from_str("13361120425250501347832030920224855036595311511513374827901659942687569213067904382419070310529480239935839308518100143939024253857202176158254361885679515473530816156355117821922648901555956036125537445852483998567339002752976575910942962150").unwrap();
 
-    static ref N1: Integer = Integer::from(1774734677598263u128);
+static N1: LazyLock<Integer> = LazyLock::new(|| Integer::from(1774734677598263u128));
-    static ref X1: Integer = Integer::from_str("11593323295292067533341930289979269834079920106030434522240627836294015987043679078861672344892723053626369715841527508395668434915559610809835295347647318767117730544084796074700752732601302352244011354650441946234192592199510139121367920997").unwrap();
+static X1: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("11593323295292067533341930289979269834079920106030434522240627836294015987043679078861672344892723053626369715841527508395668434915559610809835295347647318767117730544084796074700752732601302352244011354650441946234192592199510139121367920997").unwrap());
 
-    static ref N2: Integer = Integer::from(10000000000000000u128);
+static M: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("14004392365098131090160062970945115111185775413941111064876648140973294115502980816410773368597517292734034227298996122159833675150497554142801209096513652073059992938078366061434391648276904643753267405058183481162693381822800709938988762923").unwrap());
-    static ref X2: Integer = Integer::from_str("12451812012967875768280645960359102621677777894853024330321329610110355503343897740935595925071894025774585740051400274576363979250507927352038651542641174781860822343081975931661658111525566916416897092390763978119448659635732847002032508677").unwrap();
+static E: LazyLock<Integer> = LazyLock::new(|| Integer::from(65537));
 
-    static ref M: Integer = Integer::from_str("14004392365098131090160062970945115111185775413941111064876648140973294115502980816410773368597517292734034227298996122159833675150497554142801209096513652073059992938078366061434391648276904643753267405058183481162693381822800709938988762923").unwrap();
+static A: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("1466928606874115117499939299261").unwrap());
-    static ref E: Integer = Integer::from(65537);
+static B: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("49119078231137394008451554322").unwrap());
-
-    static ref A: Integer = Integer::from_str("1466928606874115117499939299261").unwrap();
-    static ref B: Integer = Integer::from_str("49119078231137394008451554322").unwrap();
-);
 
 fn main() {
-    let f = faulhaber_equation_from_file("res/06_faulhaber_coefficient_65537.log").unwrap();
+    let f = faulhaber_formula_from_file("res/06_faulhaber_coefficient_65537.log").unwrap();
 
     let n: Integer = Integer::from(10000000000000000u128);
     let x = (X1.clone() + f(n.clone()) - f(N1.clone())).modulo(&M);
     println!("{:?}", x);
     println!("{:?}", submit(n, x).unwrap());
 
+    // Use the submission server as an oracle to find the `n` at which `x` needs to be doubles.
     // let (mut low, mut high) = (
     //     Integer::from(1774734677598262u128),
     //     Integer::from(1774734677598263u128),
@@ -55,19 +51,17 @@ fn main() {
     // }
 }
 
-fn step(mut n: Integer, mut x: Integer, mut temp1: Integer, mut temp2: Integer) -> (Integer, Integer, Integer, Integer) {
+/// Computes one step of the challenge.
+fn step(mut n: Integer, mut x: Integer) -> (Integer, Integer) {
     n += 1;
 
     let b: &Integer = &B;
 
     // a = pow(n, e, m)
-    temp1.assign(&n);
+    let a = n.clone().pow_mod(&E, &M).unwrap();
-    let a = temp1.pow_mod(&E, &M).unwrap();
 
     // if (a % A == b) {
-    temp2.assign(&a);
+    if a.clone().modulo(&A).eq(b) {
-    let c = temp2.modulo(&A);
-    if c.eq(b) {
         // x += x
         x *= 2;
     }
@@ -76,19 +70,18 @@ fn step(mut n: Integer, mut x: Integer, mut temp1: Integer, mut temp2: Integer)
     // x %= m
     x = x.add(&a).modulo(&M);
 
-    (n, x, a, c)
+    (n, x)
 }
 
-
+fn faulhaber_formula(n: usize) -> impl Fn(Integer) -> Integer {
-fn faulhaber_equation(n: usize) -> impl Fn(Integer) -> Integer {
     let coefficients = faulhaber_triangle(n);
     for (i, coeff) in coefficients.iter().enumerate() {
         println!("{i} = {coeff}");
     }
-    faulhaber_equation_from_coefficients(coefficients)
+    faulhaber_formula_from_coefficients(coefficients)
 }
 
-fn faulhaber_equation_from_file(path: &str) -> Result<impl Fn(Integer) -> Integer> {
+fn faulhaber_formula_from_file(path: &str) -> Result<impl Fn(Integer) -> Integer> {
     let mut coefficients = Vec::new();
 
     let file = File::open(path)?;
@@ -103,10 +96,10 @@ fn faulhaber_equation_from_file(path: &str) -> Result<impl Fn(Integer) -> Intege
     sum.modulo_mut(&M);
     println!("{:?}", sum);
 
-    Ok(faulhaber_equation_from_coefficients(coefficients))
+    Ok(faulhaber_formula_from_coefficients(coefficients))
 }
 
-fn faulhaber_equation_from_coefficients(coefficients: Vec<Integer>) -> impl Fn(Integer) -> Integer {
+fn faulhaber_formula_from_coefficients(coefficients: Vec<Integer>) -> impl Fn(Integer) -> Integer {
     move |x| {
         let mut result = Integer::from(0);
         let mut temp = Integer::from(0);
@@ -127,6 +120,7 @@ fn faulhaber_equation_from_coefficients(coefficients: Vec<Integer>) -> impl Fn(I
     }
 }
 
+/// Computes the coefficients of the Faulhaber's formula.
 fn faulhaber_triangle(n: usize) -> Vec<Integer> {
     let neg1 = Integer::from(-1);
     let mut inv = Vec::with_capacity(n + 10);

src/bin/07_weird_assembly_machine.rs

@@ -1,11 +1,11 @@
 use lib::submit;
-use lib::challenges::c7_weird_assembly_machine::f_n;
+use lib::challenges::c7_weird_assembly_machine::h_n;
 
 const N: u64 = 979607657800000055;
 const X: u64 = 10962444957429324784;
 
 fn main() {
-    let (n, x) = f_n(N, X, 1_000_000_000_000_000_000u64 - N);
+    let (n, x) = h_n(N, X, 1_000_000_000_000_000_000u64 - N);
     println!("n = {n}");
     println!("x = {x}");
     submit(n, x).unwrap();

src/bin/08_revisit_everything.rs

@@ -1,14 +1,12 @@
 #![allow(dead_code)]
-// You can change the color of your name without changing your name.
+use std::sync::LazyLock;
-
-use lazy_static::lazy_static;
 use lib::submit_with_name;
-use rug::ops::{DivRounding, Pow};
+use rug::ops::DivRounding;
 use rug::Integer;
 use std::str::FromStr;
 
-lazy_static!(
+// You can change the color of your name without changing your name.
-    static ref M: Vec<Integer> = vec![
+static M: LazyLock<Vec<Integer>> = LazyLock::new(|| vec![
     Integer::from_str("1434008120931012805118743381511953470053626771934922366720474361817092344508461315782084314493561729943207476618986862630642339876124303277669871276872966561372584096756184146218943438497504108129008248947186295903702650936563195517405177267").unwrap(),
     Integer::from_str("2279983661166952569412337967792106681853682761140508555222469060830820310854240357968620360297575902950280777825697828457195462861233847516393870602678279643129330544204145040751369969379909048248974150190225328726111083312867874886821021103").unwrap(),
     Integer::from_str("2403618920217682814630057320815015451780244245370783386150600183266752801851444036459202928614238339117073052233115617730895326577436837775969446809467396763885076993639257102975158794586432834588823770619549927566204909745661463923650207527").unwrap(),
@@ -51,16 +49,16 @@ lazy_static!(
     Integer::from_str("2861034394438211841574954026003099819138101239247590122220350015475642835378420417008259980687528330087930738069620032709655292858712710050922359392413494086067180601383341612168193292772028605966992134213209023470256124404157207490432001519").unwrap(),
     Integer::from_str("2192496740130688243467014868961425982524426805724142867736885035473886629020046845749143690992453345556925544037271383038390660805714030629830845497904446979103911346917405936472233104694103049940390437540539269358666128436739707024829933171").unwrap(),
     Integer::from_str("4729254672091433598483706976591610165407510022326154887172965802144851945337220063633854456109688411742113721031379206359782182729020553179365019549633309936476652959201812418790254033614677768930428905990768941807243900642422321011756634063").unwrap(),
-    ];
+]);
 
-    static ref E: Integer = Integer::from(65537);
+static E: LazyLock<Integer> = LazyLock::new(|| Integer::from(65537));
-    static ref E_100: Integer = Integer::from(65537).pow(100);
-    static ref E_1000: Integer = Integer::from(65537).pow(1000);
 
-    static ref P: Integer = Integer::from_str("2134638905903015345595412931439525422327695207079839833349799642610037970639957457078422305821013930668706217301787851463").unwrap();
+/// the first prime factor of [`M[30]`](M)
-    static ref Q: Integer = Integer::from_str("2134638905903015345595412931439525422327695207079839833349799642610037970639957457078422305821013930668706217301787851473").unwrap();
+static P: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("2134638905903015345595412931439525422327695207079839833349799642610037970639957457078422305821013930668706217301787851463").unwrap());
-    static ref PHI: Integer = Integer::from_str("4556683258594822402855414380362620295231673046713752880933967889771646856051745784462468117575177892006513392693685616565666555545842363207724851343853529903674824524238732001458342230627654145983386115997227846421784693186847971068054052064").unwrap();
+/// the second prime factor of [`M[30]`](M)
-);
+static Q: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("2134638905903015345595412931439525422327695207079839833349799642610037970639957457078422305821013930668706217301787851473").unwrap());
+/// [`φ(M[30])`](M) where `φ` is Euler's totient function
+static PHI: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("4556683258594822402855414380362620295231673046713752880933967889771646856051745784462468117575177892006513392693685616565666555545842363207724851343853529903674824524238732001458342230627654145983386115997227846421784693186847971068054052064").unwrap());
 
 const LIMIT: u128 = 100_000_000_000_000_000_000;
 const NAME: &str = "           Jonah";
@@ -68,8 +66,8 @@ const N: u128 = 1000000000000000000;
 const X: &str = "3595876711108608978";
 
 fn main() {
-    assert_eq!(M[30].clone(), P.clone() * Q.clone());
+    debug_assert_eq!(M[30].clone(), P.clone() * Q.clone());
-    assert_eq!(PHI.clone(), (P.clone() - 1) * (Q.clone() - 1));
+    debug_assert_eq!(PHI.clone(), (P.clone() - 1) * (Q.clone() - 1));
 
     let truth = Integer::from(42);
     let k = Integer::from(LIMIT - N) * 100;

src/bin/main.rs

@@ -9,8 +9,8 @@ fn main() -> ExitCode {
         eprintln!("Usage: main NAME");
         return ExitCode::FAILURE;
     }
-
     let mut name = args[1].clone();
+
     loop {
         println!("\nAttempting to solve for \"{}\"", &name);
 

src/lib/challenges/c2_these_numbers_are_big.rs

@@ -1,13 +1,11 @@
+use std::sync::LazyLock;
 use std::str::FromStr;
-use lazy_static::lazy_static;
 use rug::Integer;
 use rug::integer::Order;
 use sha2::{Sha256, Digest};
 
-lazy_static!(
+static M: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("14004392365098131090160062970945115111185775413941111064876648140973294115502980816410773368597517292734034227298996122159833675150497554142801209096513652073059992938078366061434391648276904643753267405058183481162693381822800709938988762923").unwrap());
-    static ref M: Integer = Integer::from_str("14004392365098131090160062970945115111185775413941111064876648140973294115502980816410773368597517292734034227298996122159833675150497554142801209096513652073059992938078366061434391648276904643753267405058183481162693381822800709938988762923").unwrap();
+static E: LazyLock<Integer> = LazyLock::new(|| Integer::from(65537));
-    static ref E: Integer = Integer::from(65537);
-);
 
 pub fn solve(name: &str) -> (u64, Integer) {
     let mut x = sha256(name);

src/lib/challenges/c3_are_you_still_doing_this_by_hand.rs

@@ -1,24 +1,44 @@
-use lazy_static::lazy_static;
 use rug::Integer;
 use std::collections::HashMap;
-use std::io::{stdout, Write};
+use std::fs::File;
+use std::io::Write;
+use std::sync::LazyLock;
 use tqdm::tqdm;
 
+/// the base of the discrete logarithm
+const G: u64 = 42;
+/// the stride value of the Baby-Step-Giant-Step algorithm, controlling the space-time-tradeoff
+const S: u64 = 5341666;
+/// the modul of the discrete logarithm
 const P: u64 = 12345679943u64;
 
-lazy_static!(
+/// the precomputed baby steps
-    static ref BABY_STEPS: Vec<u64> = std::fs::read("res/03_baby_steps.bin").unwrap()
+static BABY_STEPS: LazyLock<Vec<u64>> = LazyLock::new(|| {
+    let path = "res/03_baby_steps.bin";
+    if !std::fs::exists(path).unwrap() {
+        precompute_baby_steps(G, P, S, &mut File::create(path).unwrap());
+    }
+
+    std::fs::read(path).unwrap()
         .chunks_exact(8)
         .map(|chunk| u64::from_be_bytes(chunk.try_into().unwrap()))
-        .collect();
+        .collect()
+});
 
-    static ref GIANT_STEPS: HashMap<u64, usize> = std::fs::read("res/03_giant_steps.bin").unwrap()
+/// the precomputed giant steps
+static GIANT_STEPS: LazyLock<HashMap<u64, usize>> = LazyLock::new(|| {
+    let path = "res/03_giant_steps.bin";
+    if !std::fs::exists(path).unwrap() {
+        precompute_giant_steps(G, P, S, &mut File::create(path).unwrap());
+    }
+
+    std::fs::read(path).unwrap()
         .chunks_exact(8)
         .map(|chunk| u64::from_be_bytes(chunk.try_into().unwrap()))
         .enumerate()
         .map(|(idx, step)| (step, idx))
-        .collect();
+        .collect()
-);
+});
 
 pub fn solve(n: u64, x: Integer) -> (u64, Integer) {
     let x = x.modulo(&Integer::from(P - 1)).to_u64().unwrap();
@@ -33,6 +53,8 @@ pub fn solve(n: u64, x: Integer) -> (u64, Integer) {
     (n, Integer::from(x))
 }
 
+/// Quickly computes the discrete logarithm of `b` to the base [`G`] modulo [`M`] using the Baby-Step-Giant-Step
+/// algorithm with precomputed steps
 fn log42_mod_p(b: u64) -> Option<u64> {
     if b % P == 1 {
         return Some(0);
@@ -51,36 +73,33 @@ fn log42_mod_p(b: u64) -> Option<u64> {
     None
 }
 
-pub fn precompute() {
+/// Precomputes the giant steps for use in the Baby-Step-Giant-Step algorithm for a fixed base `g` and modul `m` using a
-    let g = 42u64;
+/// stride of `s`.
-    let m = P;
+fn precompute_giant_steps(g: u64, m: u64, s: u64, out: &mut impl Write) {
-    let s = 5341666;
-    precompute_giant_steps(g, m, s);
-    precompute_baby_steps(g, m, s);
-}
-
-fn precompute_giant_steps(g: u64, m: u64, s: u64) {
     let g = g as u128;
     let m = m as u128;
     let mut a = 1u128;
     for _ in tqdm(0..s) {
-        stdout().write_all(&(a as u64).to_be_bytes()).unwrap();
+        out.write_all(&(a as u64).to_be_bytes()).unwrap();
         a *= g;
         a %= m;
     }
 }
 
-fn precompute_baby_steps(g: u64, m: u64, s: u64) {
+/// Precomputes the baby steps for use in the Baby-Step-Giant-Step algorithm for a fixed base `g` and modul `m`  using a
+/// stride of `s`.
+fn precompute_baby_steps(g: u64, m: u64, s: u64, out: &mut impl Write) {
     let gs = pow(g, s, m) as u128;
     let m= m as u128;
     let mut a = gs;
     for _ in tqdm(1..=(m as u64 / s + 1)) {
-        stdout().write_all(&(a as u64).to_be_bytes()).unwrap();
+        out.write_all(&(a as u64).to_be_bytes()).unwrap();
         a *= gs;
         a %= m;
     }
 }
 
+/// Computes the discrete logarithm of `b` to the base `g` modulo `m` using the Baby-Step-Giant-Step algorithm.
 fn log(g: u64, b: u64, m: u64) -> Option<u64> {
     let g: u128 = g as u128;
     let b: u128 = b as u128;
@@ -114,6 +133,7 @@ fn log(g: u64, b: u64, m: u64) -> Option<u64> {
     None
 }
 
+/// Computes the `k`-th power of `a` modulo `m`.
 fn pow(a: u64, mut k: u64, m: u64) -> u64 {
     let mut a: u128 = a as u128;
     let m: u128 = m as u128;

src/lib/challenges/c5_what_the_bf.rs

@@ -21,12 +21,12 @@ pub fn solve(n: u64, x: Integer) -> (u64, Integer) {
     (LIMIT, x * b % &M)
 }
 
-
-const A: u128 =   909_090_909_091u128; // (10 * b + 1) / 11
-const B: u128 = 1_000_000_000_000u128; // 10^12
-const C: u128 =   999_999_999_989u128; // b - 11
-const D: u128 =   999_999_999_999u128; // b -  1
 fn f(mut x: u128) -> u128 {
+    const A: u128 =   909_090_909_091u128; // (10 * b + 1) / 11
+    const B: u128 = 1_000_000_000_000u128; // 10^12
+    const C: u128 =   999_999_999_989u128; // b - 11
+    const D: u128 =   999_999_999_999u128; // b -  1
+
     x = x * A % B;
     x = (x * C + D) / B;
     x

src/lib/challenges/c6_automation_is_not_enough.rs

@@ -1,26 +1,21 @@
-use lazy_static::lazy_static;
 use rug::Integer;
 use std::str::FromStr;
+use std::sync::LazyLock;
 
 const START: u64 = 1_000_000_000_000u64;
 const LIMIT: u64 = 10_000_000_000_000_000u64;
 
-lazy_static!(
+static M: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("14004392365098131090160062970945115111185775413941111064876648140973294115502980816410773368597517292734034227298996122159833675150497554142801209096513652073059992938078366061434391648276904643753267405058183481162693381822800709938988762923").unwrap());
-    static ref M: Integer = Integer::from_str("14004392365098131090160062970945115111185775413941111064876648140973294115502980816410773368597517292734034227298996122159833675150497554142801209096513652073059992938078366061434391648276904643753267405058183481162693381822800709938988762923").unwrap();
+static A: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("10729297455904899337681752672816753703351288544833760635567859176397566160330812285369370751389224534974913042757043771146367160829669925123791471756026119030734890865062863499420767799283504416995775836275660636668989077836006690621539265605").unwrap());
-    static ref A: Integer = Integer::from_str("10729297455904899337681752672816753703351288544833760635567859176397566160330812285369370751389224534974913042757043771146367160829669925123791471756026119030734890865062863499420767799283504416995775836275660636668989077836006690621539265605").unwrap();
+static B: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("4997609466256208183077203585670710326160976219126614124062259398288517298185253986607627790890962248558793881836308854443463332741665631247256917127102588793451033551034614994254514161235462726178612824897626185944163885786520174491419225456").unwrap());
-    static ref B: Integer = Integer::from_str("4997609466256208183077203585670710326160976219126614124062259398288517298185253986607627790890962248558793881836308854443463332741665631247256917127102588793451033551034614994254514161235462726178612824897626185944163885786520174491419225456").unwrap();
-);
 
 pub fn solve(n: u64, x: Integer) -> (u64, Integer) {
     assert_eq!(n, START);
-    let m: &Integer = &M;
-    let a: &Integer = &A;
-    let b: &Integer = &B;
     
     let mut x = x;
-    x = (x + a) % m;
+    x = (x + &*A) % &*M;
-    x = x * 2 % m;
+    x = x * 2 % &*M;
-    x = (x + b) % m;
+    x = (x + &*B) % &*M;
 
     (LIMIT, x)
 }

src/lib/challenges/c7_weird_assembly_machine.rs

@@ -1,11 +1,10 @@
 use std::fs::File;
 use std::io::{BufRead, BufReader};
 use std::str::FromStr;
-use lazy_static::lazy_static;
+use std::sync::LazyLock;
 use rug::Integer;
 
-lazy_static!(
+static DATA: LazyLock<Vec<u64>> = LazyLock::new(|| {
-    static ref DATA: Vec<u64> = {
     let file = File::open("./res/07_weird_assembly_machine.data");
     let lines = BufReader::new(file.unwrap()).lines();
 
@@ -14,19 +13,21 @@ lazy_static!(
         data.push(u64::from_str(&line.unwrap()).unwrap());
     }
     data
-    };
+});
-);
 
 const LIMIT: u64 = 1_000_000_000_000_000_000u64;
 
 pub fn solve(n: u64, x: Integer) -> (u64, Integer) {
     let x = x.to_u64_wrapping();
-    let (n, x) = f_n(n, x, LIMIT - n);
+    let (n, x) = h_n(n, x, LIMIT - n);
     (n, Integer::from(x))
 }
 
+fn h(x: u64, n: u64) -> u64 {
+    g(sub(f(x), n))
+}
 
-pub fn f_n(mut n: u64, mut x: u64, k: u64) -> (u64, u64) {
+pub fn h_n(mut n: u64, mut x: u64, k: u64) -> (u64, u64) {
     n += 1;
     x = sub(f(x), n);
 
@@ -45,6 +46,28 @@ pub fn f_n(mut n: u64, mut x: u64, k: u64) -> (u64, u64) {
     (n, x)
 }
 
+fn f(x: u64) -> u64 {
+    evaluate(x, &DATA[..128])
+}
+
+fn g(x: u64) -> u64 {
+    evaluate(x, &DATA[128..])
+}
+
+/// Quickly computes [`f`](f)([`g`](g)(x)).
+fn fg(x: u64) -> u64 {
+    !x.rotate_left(17)
+}
+
+/// Computes [`fg`](fg)(...[`fg`](fg)(x)...) where [`fg`] is applied `n` times.
+fn fg_n(mut x: u64, n: u64) -> u64 {
+    for _ in 0..n%64 {
+        x = fg(x);
+    }
+    x
+}
+
+/// Computes the sum from `i = 1` to `k` over `fg^(k-i)(n + i)`.
 fn fg_sum(n: u64, k: u64) -> u64 {
     let mut sum = 0u64;
     for i in 1..=k {
@@ -53,6 +76,7 @@ fn fg_sum(n: u64, k: u64) -> u64 {
     sum
 }
 
+/// Quickly computes `fg_sum` when `k` is divisible by `192`.
 fn fast_fg_sum(n: u64, k: u64) -> u64 {
     debug_assert!(k % 192 == 0);
     let mut result = fg_sum(n, 0);
@@ -60,12 +84,13 @@ fn fast_fg_sum(n: u64, k: u64) -> u64 {
     result
 }
 
-fn f(x: u64) -> u64 {
+/// Evaluates a polynomial over `GF(2)[X] / (X^64 + 1)`
-    evaluate(x, &DATA[..128], &DATA[..128])
+fn evaluate(x: u64, data: &[u64]) -> u64 {
-}
+    let mut out = 0;
-
+    for i in 0..data.len() {
-fn g(x: u64) -> u64 {
+        out = xor_mul(out, x) ^ data[i];
-    evaluate(x, &DATA[128..], &DATA[128..])
+    }
+    out
 }
 
 fn add(a: u64, b: u64) -> u64 {
@@ -80,27 +105,6 @@ fn sub(x: u64, mut n: u64) -> u64 {
     x.wrapping_sub(n)
 }
 
-fn fg(x: u64) -> u64 {
-    !x.rotate_left(17)
-}
-
-fn fg_n(mut x: u64, n: u64) -> u64 {
-    for _ in 0..n%64 {
-        x = fg(x);
-    }
-    x
-}
-
-fn evaluate(x: u64, data_even: &[u64], data_odd: &[u64]) -> u64 {
-    let data = if x.count_ones() % 2 == 0 { data_even } else { data_odd };
-
-    let mut out = 0;
-    for i in 0..data.len() {
-        out = xor_mul(out, x) ^ data[i];
-    }
-    out
-}
-
 #[cfg(not(all(target_arch = "x86_64", target_feature = "pclmulqdq")))]
 fn xor_mul(a: u64, mut b: u64) -> u64 {
     let mut x: u64 = 0;

src/lib/challenges/c8_revisit_everything.rs

@@ -1,26 +1,24 @@
 use rug::ops::DivRounding;
 use rug::Integer;
 use std::str::FromStr;
+use std::sync::LazyLock;
 
-const PHI: &str = "4556683258594822402855414380362620295231673046713752880933967889771646856051745784462468117575177892006513392693685616565666555545842363207724851343853529903674824524238732001458342230627654145983386115997227846421784693186847971068054052064";
+static PHI: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("4556683258594822402855414380362620295231673046713752880933967889771646856051745784462468117575177892006513392693685616565666555545842363207724851343853529903674824524238732001458342230627654145983386115997227846421784693186847971068054052064").unwrap());
-const M: &str = "4556683258594822402855414380362620295231673046713752880933967889771646856051745784462468117575177892006513392693685616569935833357648393898915677206732580748330214938398411668157941515847730087263301030154072458063812554524260405671629754999";
+static M: LazyLock<Integer> = LazyLock::new(|| Integer::from_str("4556683258594822402855414380362620295231673046713752880933967889771646856051745784462468117575177892006513392693685616569935833357648393898915677206732580748330214938398411668157941515847730087263301030154072458063812554524260405671629754999").unwrap());
-const E: u64 = 65537;
+static E: LazyLock<Integer> = LazyLock::new(|| Integer::from(65537));
+static TRUTH: LazyLock<Integer> = LazyLock::new(|| Integer::from(42));
 const LIMIT: u128 = 100_000_000_000_000_000_000;
 
 pub fn solve(n: u64, x: Integer) -> Result<(u128, Integer), u32> {
-    let truth = Integer::from(42);
-    let phi = Integer::from_str(PHI).unwrap();
-    let m = Integer::from_str(M).unwrap();
-
     let k = Integer::from(LIMIT - n as u128) * 100;
-    let e = Integer::from(E).pow_mod(&k, &phi).unwrap();
+    let e = E.clone().pow_mod(&k, &PHI).unwrap();
-    let w: u32 = x.clone().modulo(&truth).try_into().unwrap();
+    let w: u32 = x.clone().modulo(&TRUTH).try_into().unwrap();
     if w != 30 {
         return Err(w);
     }
 
-    let mut y = x.clone().div_floor(&truth);
+    let mut y = x.clone().div_floor(&*TRUTH);
-    y = y.pow_mod(&e, &m).unwrap();
+    y = y.pow_mod(&e, &M).unwrap();
 
     let x: Integer = y * 42 + w;
     Ok((LIMIT, x))