add 95, 17

lib/primes/benches/benchmark.rs

@@ -10,5 +10,15 @@ fn bench_primes_between_10e5_and_10e6(c: &mut Criterion) {
     });
 }
 
-criterion_group!(benches, bench_primes_between_10e5_and_10e6);
+fn bench_primes_between_10_and_10e6(c: &mut Criterion) {
+    c.bench_function("primes 10 to 10e6", |b| {
+        b.iter(|| Primes::get_between(10, 1_000_000))
+    });
+}
+
+criterion_group!(
+    benches,
+    bench_primes_between_10_and_10e6,
+    bench_primes_between_10e5_and_10e6
+);
 criterion_main!(benches);

lib/proper_divisors/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "proper_divisors"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+#num = "0.4.3"
+
+[dev-dependencies]
+rstest = "0.25.0"

lib/proper_divisors/src/lib.rs

@@ -0,0 +1,82 @@
+use std::collections::HashMap;
+
+#[derive(Debug)]
+pub struct ProperDivisors {
+    map: HashMap<usize, Vec<usize>>,
+    pub min: usize,
+    pub max: usize,
+}
+
+impl ProperDivisors {
+    pub fn get_between(smaller: usize, larger: usize) -> Self {
+        let mut result = HashMap::new();
+
+        for number in smaller..=larger {
+            let mut divisors = vec![1];
+
+            let limit = usize::isqrt(number);
+
+            for i in (2..=limit).rev() {
+                if number % i == 0 {
+                    let div_1 = i;
+                    let div_2 = number / i;
+
+                    divisors.push(div_1);
+
+                    if div_1 != div_2 {
+                        divisors.push(div_2);
+                    }
+                }
+            }
+
+            divisors.sort_unstable();
+            result.insert(number, divisors);
+        }
+
+        Self {
+            map: result,
+            min: smaller,
+            max: larger,
+        }
+    }
+
+    pub fn get(&self, number: usize) -> &[usize] {
+        self.map.get(&number).unwrap()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use rstest::rstest;
+
+    use crate::ProperDivisors;
+
+    #[rstest]
+    #[case(6, vec![1, 2, 3])]
+    #[case(28, vec![1, 2, 4, 7, 14])]
+    #[case(12_496, vec![1, 2, 4, 8, 11, 16, 22, 44, 71, 88, 142, 176, 284, 568, 781, 1136, 1562, 3124, 6248])]
+    fn one_proper_divisor(#[case] input: usize, #[case] expected: Vec<usize>) {
+        let pd = ProperDivisors::get_between(input, input + 1);
+
+        assert_eq!(pd.get(input), expected);
+    }
+
+    #[test]
+    fn all_proper_divisors() {
+        let pd = ProperDivisors::get_between(6, 30);
+
+        assert_eq!(pd.get(6), &[1, 2, 3]);
+        assert_eq!(pd.get(28), &[1, 2, 4, 7, 14]);
+
+        println!("{:?}", pd.get(8));
+
+        let pd = ProperDivisors::get_between(12_496, 12_497);
+        assert_eq!(
+            pd.get(12_496),
+            &[
+                1, 2, 4, 8, 11, 16, 22, 44, 71, 88, 142, 176, 284, 568, 781, 1136, 1562, 3124, 6248
+            ]
+        );
+    }
+}

src/euler17/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "euler17"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+
+[dev-dependencies]
+rstest = "0.25.0"

src/euler17/src/main.rs

@@ -0,0 +1,110 @@
+fn main() {
+    let result: usize = (1..=1000).map(convert_number).sum();
+    println!("{result}");
+}
+
+fn convert_number(number: usize) -> usize {
+    if number == 1_000 {
+        return 11;
+    };
+
+    let mut sum = 0;
+
+    if has_hundreds_digits(number) {
+        sum += convert_hundreds(number);
+    }
+
+    if has_hundreds_digits(number) && has_tens_or_single_digits(number) {
+        sum += 3; // "and"
+    }
+
+    if has_tens_or_single_digits(number) {
+        sum += convert_tens_and_single_digits(number);
+    }
+
+    sum
+}
+
+fn convert_tens_and_single_digits(number: usize) -> usize {
+    let number = get_tens_and_single_digits(number);
+    let mut result = match number {
+        x if x < 10 => convert_digit_to_letters(x),
+        10 => 3,
+        11 => 6,
+        12 => 6,
+        13 => 8,
+        14 => 8,
+        15 => 7,
+        16 => 7,
+        17 => 9,
+        18 => 8,
+        19 => 8,
+        x if x < 40 => 6,  // twenty, thirty are all of length 6
+        x if x < 70 => 5,  // forty, fifty, sixty
+        x if x < 80 => 7,  // seventy
+        x if x < 100 => 6, // eighty, ninety
+        _ => panic!(),
+    };
+
+    if number > 20 {
+        result += convert_digit_to_letters(number % 10);
+    }
+
+    result
+}
+
+fn get_tens_and_single_digits(number: usize) -> usize {
+    number % 100
+}
+
+fn has_tens_or_single_digits(number: usize) -> bool {
+    get_tens_and_single_digits(number) > 0
+}
+
+fn convert_hundreds(number: usize) -> usize {
+    let hundreds = get_hundreds(number);
+    let letters = convert_digit_to_letters(hundreds);
+    letters + 7
+}
+
+fn convert_digit_to_letters(number: usize) -> usize {
+    match number {
+        0 => 0,
+        1 => 3,
+        2 => 3,
+        3 => 5,
+        4 => 4,
+        5 => 4,
+        6 => 3,
+        7 => 5,
+        8 => 5,
+        9 => 4,
+        _ => unreachable!("should not happen if code is correct"),
+    }
+}
+
+fn has_hundreds_digits(number: usize) -> bool {
+    get_hundreds(number) > 0
+}
+
+fn get_hundreds(number: usize) -> usize {
+    number / 100
+}
+
+#[cfg(test)]
+mod tests {
+
+    use rstest::rstest;
+
+    #[rstest]
+    #[case(1, 5, 19)]
+    #[case(115, 115, 20)]
+    #[case(342, 342, 23)]
+    #[case(1000, 1000, 11)]
+    fn chain(#[case] min: usize, #[case] max: usize, #[case] expected: usize) {
+        use crate::convert_number;
+
+        let sum: usize = (min..=max).map(convert_number).sum();
+        assert_eq!(sum, expected);
+    }
+}

src/euler95/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "euler95"
 version = "0.1.0"
-edition = "2021"
+edition = "2024"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -10,4 +10,7 @@ rstest = "0.17"
 
 [profile.release]
 debug = true
-lto = "fat"
+lto = "off"
+
+[dependencies]
+proper_divisors = { version = "*", path = "../../lib/proper_divisors" }

src/euler95/src/main.rs

@@ -1,118 +1,146 @@
-use std::collections::HashSet;
+use proper_divisors::ProperDivisors;
+use std::collections::HashMap;
 
+const MIN: usize = 2;
 const MAX: usize = 1_000_000;
 
 fn main() {
-    let mut chains = vec![];
+    let proper_divisors_map = ProperDivisors::get_between(MIN, MAX);
+    let mut number_divisor_sum_map = NumberDivisorSumMap::build(proper_divisors_map);
 
-    let mut part_of_any_chain = HashSet::new();
+    let mut longest_chain = vec![];
 
-    for current in 1..MAX {
+    for number in MIN..MAX {
-        if part_of_any_chain.contains(&current) {
+        if *number_divisor_sum_map.get(&number).unwrap_or(&1) == 1 {
+            // if equals 1, then it's prime and useless
+            // if it's `None`, it was already used
             continue;
         }
-        try_build_chain_from_number(MAX, current, &mut chains, &mut part_of_any_chain);
+        if let Some(chain) = try_build_chain_from_number(number, &mut number_divisor_sum_map) {
+            dbg!(&chain, &longest_chain);
+            if chain.len() > longest_chain.len() {
+                longest_chain = chain;
+            }
+        }
     }
 
-    chains.sort_by_key(|chain| chain.len());
+    dbg!(&longest_chain);
 
-    let longest = chains.last().unwrap();
+    let smallest = longest_chain.iter().min().unwrap().to_owned();
-
-    let smallest = longest.iter().min().unwrap().to_owned();
 
     println!("{smallest}");
 }
 
-fn build_proper_divisors(max: usize) -> Vec<Vec<usize>> {
+#[derive(Debug)]
-    todo!()
+struct NumberDivisorSumMap {
+    map: HashMap<usize, usize>,
+    max: usize,
+}
+
+impl NumberDivisorSumMap {
+    fn build(pd: ProperDivisors) -> Self {
+        let mut number_divisor_sum_map = HashMap::new();
+
+        for number in pd.min..=pd.max {
+            let sum: usize = pd.get(number).iter().sum();
+            number_divisor_sum_map.insert(number, sum);
+        }
+        Self {
+            map: number_divisor_sum_map,
+            max: pd.max,
+        }
+    }
+
+    fn get(&self, key: &usize) -> Option<&usize> {
+        self.map.get(key)
+    }
+
+    fn remove(&mut self, key: &usize) {
+        self.map.remove(key);
+    }
+
+    fn remove_all(&mut self, keys: &[usize]) {
+        for key in keys {
+            self.remove(key);
+        }
+    }
 }
 
 fn try_build_chain_from_number(
-    max: usize,
+    mut number: usize,
-    mut current: usize,
+    number_divisor_sum_map: &mut NumberDivisorSumMap,
-    chains: &mut Vec<Vec<usize>>,
+) -> Option<Vec<usize>> {
-    part_of_any_chain: &mut HashSet<usize>,
-) {
     let mut maybe_chain = vec![];
 
+    let mut debug = false;
+    if number == 1064 {
+        debug = true;
+    }
+
     loop {
-        maybe_chain.push(current);
+        if debug {
+            dbg!(number);
+            dbg!(&maybe_chain);
+        }
+        maybe_chain.push(number);
 
-        let next: usize = get_proper_divisors(current).into_iter().sum();
+        let next: usize = match number_divisor_sum_map.get(&number) {
+            Some(number) => *number,
+            None => break None,
+        };
 
-        if next > max || next == 0 {
+        if next > number_divisor_sum_map.max || next == 1 || next == number {
-            break;
+            number_divisor_sum_map.remove_all(&maybe_chain);
+            break None;
         }
 
-        if maybe_chain.contains(&next) {
+        if maybe_chain.contains(&next) && maybe_chain.len() > 1
-            if maybe_chain.len() > 1 && *maybe_chain.first().unwrap() == next {
+        //&& *maybe_chain.first().unwrap() == next
-                for number in &maybe_chain {
+        {
-                    part_of_any_chain.insert(*number);
-                }
             println!("{}", maybe_chain.first().unwrap());
-                chains.push(maybe_chain);
+
-            }
+            number_divisor_sum_map.remove_all(&maybe_chain);
-            break;
+            break Some(maybe_chain);
         }
 
-        current = next;
+        number = next;
     }
 }
 
-fn get_proper_divisors(x: usize) -> Vec<usize> {
-    let mut result = vec![1];
-
-    let limit = x / 2 + 1;
-
-    for i in 2..limit {
-        if result.contains(&i) {
-            break;
-        }
-
-        if x % i == 0 {
-            let div_1 = i;
-            let div_2 = x / i;
-            result.push(div_1);
-
-            if div_2 != div_1 {
-                result.push(div_2);
-            }
-        }
-    }
-
-    result.sort_unstable();
-    result
-}
-
 #[cfg(test)]
 mod tests {
 
     use rstest::rstest;
 
-    #[rstest]
+    use crate::{NumberDivisorSumMap, try_build_chain_from_number};
-    #[case(6, vec![1, 2, 3])]
+    use proper_divisors::ProperDivisors;
-    #[case(28, vec![1, 2, 4, 7, 14])]
-    #[case(12_496, vec![1, 2, 4, 8, 11, 16, 22, 44, 71, 88, 142, 176, 284, 568, 781, 1136, 1562, 3124, 6248])]
-    fn proper_divisor(#[case] input: usize, #[case] expected: Vec<usize>) {
-        use crate::get_proper_divisors;
-
-        assert_eq!(get_proper_divisors(input), expected);
-    }
 
     #[rstest]
-    #[case(220, vec![vec![220, 284]])]
+    #[case(220, vec![220, 284])]
-    #[case(12_496, vec![vec![12_496, 14_288, 15_472, 14_536, 14_264]])]
+    #[case(12_496, vec![12_496, 14_288, 15_472, 14_536, 14_264])]
-    fn chain(#[case] input: usize, #[case] expected: Vec<Vec<usize>>) {
+    fn chain(#[case] input: usize, #[case] expected: Vec<usize>) {
-        use std::collections::HashSet;
+        let larger = expected.iter().max().unwrap().to_owned() + 1;
 
-        use crate::try_build_chain_from_number;
+        let pd = ProperDivisors::get_between(2, larger);
+        let mut number_divisor_sum_map = NumberDivisorSumMap::build(pd);
 
-        let max = expected.iter().flatten().max().unwrap().to_owned();
+        let chain = try_build_chain_from_number(input, &mut number_divisor_sum_map).unwrap();
-        let mut part_of_any_chain = HashSet::new();
 
-        let mut chains = vec![];
+        assert_eq!(chain, expected);
-        try_build_chain_from_number(max, input, &mut chains, &mut part_of_any_chain);
+    }
 
-        assert_eq!(chains, expected);
+    #[test]
+    fn all_chains() {
+        let smaller = 2;
+        let larger = 16_000;
+
+        let pd = ProperDivisors::get_between(smaller, larger);
+        let mut number_divisor_sum_map = NumberDivisorSumMap::build(pd);
+
+        let chain = try_build_chain_from_number(220, &mut number_divisor_sum_map).unwrap();
+        assert_eq!(chain, vec![220, 284]);
+
+        let chain = try_build_chain_from_number(12_496, &mut number_divisor_sum_map).unwrap();
+        assert_eq!(chain, vec![12_496, 14_288, 15_472, 14_536, 14_264]);
     }
 }