Solutions for 2022, as well as 2015-2018 and 2019 up to day 11

2019/day04_secure_container/Cargo.toml

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+[package]
+name = "day04_secure_container"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2019/day04_secure_container/challenge.txt

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+You arrive at the Venus fuel depot only to discover it's protected by a password. The Elves had written the password on a sticky note, but someone threw it out.
+
+However, they do remember a few key facts about the password:
+
+* It is a six-digit number.
+* The value is within the range given in your puzzle input.
+* Two adjacent digits are the same (like `22` in `1*22*345`).
+* Going from left to right, the digits *never decrease*; they only ever increase or stay the same (like `111123` or `135679`).
+
+Other than the range rule, the following are true:
+
+* `111111` meets these criteria (double `11`, never decreases).
+* `2234*50*` does not meet these criteria (decreasing pair of digits `50`).
+* `123789` does not meet these criteria (no double).
+
+*How many different passwords* within the range given in your puzzle input meet these criteria?
+
+Your puzzle answer was `921`.
+
+\--- Part Two ---
+----------
+
+An Elf just remembered one more important detail: the two adjacent matching digits *are not part of a larger group of matching digits*.
+
+Given this additional criterion, but still ignoring the range rule, the following are now true:
+
+* `112233` meets these criteria because the digits never decrease and all repeated digits are exactly two digits long.
+* `123*444*` no longer meets the criteria (the repeated `44` is part of a larger group of `444`).
+* `111122` meets the criteria (even though `1` is repeated more than twice, it still contains a double `22`).
+
+*How many different passwords* within the range given in your puzzle input meet all of the criteria?
+
+Your puzzle answer was `603`.
+
+Both parts of this puzzle are complete! They provide two gold stars: \*\*
+
+At this point, you should [return to your Advent calendar](/2019) and try another puzzle.
+
+Your puzzle input was `278384-824795`.

2019/day04_secure_container/src/lib.rs

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+pub fn run(input: &str) -> (usize, usize) {
+    let range: Vec<_> = input.split('-').map(|n| n.parse::<usize>().unwrap()).collect();
+    let valid_1: Vec<_> = (range[0]..=range[1]).filter(is_valid_1).collect();
+    let first = valid_1.len();
+    let second = valid_1.into_iter().filter(is_valid_2).count();
+    (first, second)
+}
+
+fn is_valid_1(password: &usize) -> bool {
+    let mut double_found = false;
+    let mut last_digit = password % 10;
+    let mut remaining = password / 10;
+    while remaining > 0 {
+        let this_digit = remaining % 10;
+        if this_digit > last_digit {
+            return false;
+        }
+        if this_digit == last_digit {
+            double_found = true;
+        }
+        last_digit = this_digit;
+        remaining /= 10;
+    }
+    double_found
+}
+
+fn is_valid_2(password: &usize) -> bool {
+    let mut current_group_len = 1;
+    let mut last_digit = password % 10;
+    let mut remaining = password / 10;
+    while remaining > 0 {
+        let this_digit = remaining % 10;
+        if this_digit == last_digit {
+            current_group_len += 1;
+        } else if current_group_len == 2 {
+            return true;
+        } else {
+            current_group_len = 1;
+        }
+        last_digit = this_digit;
+        remaining /= 10;
+    }
+    current_group_len == 2
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs::read_to_string;
+
+    fn read_file(name: &str) -> String {
+        read_to_string(name).expect(&format!("Unable to read file: {name}")[..]).trim().to_string()
+    }
+
+    #[test]
+    fn test_sample() {
+        let sample_input = read_file("tests/sample_input");
+        assert_eq!(run(&sample_input), (36, 14));
+    }
+
+    #[test]
+    fn test_challenge() {
+        let challenge_input = read_file("tests/challenge_input");
+        assert_eq!(run(&challenge_input), (921, 603));
+    }
+}

2019/day04_secure_container/tests/challenge_input

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+278384-824795

2019/day04_secure_container/tests/sample_input

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+111200-111300