y2015d5

y2015/src/bin/d5.rs

@@ -0,0 +1,20 @@
+use std::fs;
+
+use y2015::days::d5;
+
+fn main() {
+    part1();
+    part2();
+}
+
+fn part1() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/5_input.txt")).unwrap();
+    println!("{}", d5::process_part1(&content));
+}
+
+fn part2() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/5_input.txt")).unwrap();
+    println!("{}", d5::process_part2(&content));
+}

y2015/src/days/d5.rs

@@ -0,0 +1,105 @@
+use std::collections::HashMap;
+
+const DISALLOWED: [(u8, u8); 4] = [(b'a', b'b'), (b'c', b'd'), (b'p', b'q'), (b'x', b'y')];
+const VOWELS: [u8; 5] = [b'a', b'e', b'i', b'o', b'u'];
+
+pub fn process_part1(input: &str) -> i32 {
+    input
+        .lines()
+        .map(|line| line.as_bytes())
+        .map(|line| {
+            let mut num_vowels = 0;
+            let mut has_double = false;
+            if VOWELS.contains(&line[0]) {
+                num_vowels += 1;
+            }
+            for window in line.windows(2) {
+                if DISALLOWED.contains(&(window[0], window[1])) {
+                    return 0;
+                }
+                if window[0] == window[1] {
+                    has_double = true;
+                }
+                if VOWELS.contains(&window[1]) {
+                    num_vowels += 1;
+                }
+            }
+            if num_vowels >= 3 && has_double {
+                return 1;
+            }
+            0
+        })
+        .sum()
+}
+
+// used the following solution to debug
+// cat input |  grep "\(..\).*\1" | grep "\(.\).\1" | wc -l
+pub fn process_part2(input: &str) -> i32 {
+    input
+        .lines()
+        .map(|line| line.as_bytes())
+        .map(|line| {
+            let mut pairs = HashMap::new();
+            let mut has_sandwich = false;
+            for window in line.windows(3) {
+                if window[0] == window[2] {
+                    has_sandwich = true;
+                    break;
+                }
+            }
+            if !has_sandwich {
+                return 0;
+            }
+            let mut last_pair = "".to_string();
+            let mut is_valid = true;
+            for window in line.windows(2) {
+                let pair = String::from_utf8(window.to_vec()).unwrap();
+                if pair == last_pair && is_valid {
+                    is_valid = false;
+                    continue;
+                }
+                is_valid = true;
+                pairs
+                    .entry(pair.clone())
+                    .and_modify(|counter| *counter += 1)
+                    .or_insert(1);
+                last_pair = pair;
+            }
+            for (_, count) in pairs.into_iter() {
+                if count >= 2 {
+                    println!("{}", String::from_utf8(line.to_vec()).unwrap());
+                    return 1;
+                }
+            }
+            0
+        })
+        .sum()
+}
+
+#[cfg(test)]
+mod tests_5 {
+    use super::*;
+
+    const INPUT1: &str = "ugknbfddgicrmopn
+aaa
+jchzalrnumimnmhp
+haegwjzuvuyypxyu
+dvszwmarrgswjxmb";
+
+    #[test]
+    fn it_works() {
+        let result = process_part1(INPUT1);
+        assert_eq!(result, 2);
+    }
+
+    const INPUT2: &str = "qjhvhtzxzqqjkmpb
+xxyxx
+uurcxstgmygtbstg
+ieodomkazucvgmuy";
+
+    #[test]
+    fn part2() {
+        let result = process_part2(INPUT2);
+        assert_eq!(result, 2);
+    }
+}

y2015/src/days/mod.rs

@@ -2,3 +2,4 @@ pub mod d1;
 pub mod d2;
 pub mod d3;
 pub mod d4;
+pub mod d5;