1 files changed, 110 insertions, 0 deletions
diff --git a/2025/d2.rs b/2025/d2.rs
new file mode 100644
index 0000000..9c2b060
--- /dev/null
+++ b/2025/d2.rs
@@ -0,0 +1,110 @@
+use aoc::fetch::fetch;
+
+struct Checker {
+    first: usize,
+    last: usize,
+}
+
+impl Checker {
+    fn new(first: usize, last: usize) -> Result<Self, ()> {
+        if first
+            .to_string()
+            .chars()
+            .next()
+            .unwrap()
+            == '0'
+        {
+            return Err(());
+        }
+
+        Ok(
+            Self {
+                first,
+                last,
+            },
+        )
+    }
+
+    fn parse_section_part1(num: usize) -> usize {
+        let s = num.to_string();
+        let len = s.len();
+        for substr_len in 1..=len / 2 {
+            if len % substr_len == 0 {
+                let first = &s[0..substr_len];
+                if s.as_bytes()
+                    .chunks(substr_len)
+                    .all(|chunk| chunk == first.as_bytes())
+                {
+                    return num;
+                }
+            }
+        }
+        0
+    }
+
+    fn parse_section_part2(num: usize) -> usize {
+        let s = num.to_string();
+        if s.len() % 2 != 0 {
+            return 0;
+        }
+        if s[0..s.len() / 2] == s[s.len() / 2..s.len()] {
+            return num;
+        }
+        0
+    }
+
+    fn parse(self, part2: bool) -> usize {
+        let mut ans = 0;
+        for i in self.first..=self.last {
+            ans += if part2 {
+                Self::parse_section_part2(i)
+            } else {
+                Self::parse_section_part1(i)
+            };
+        }
+        ans
+    }
+}
+
+fn run(part2: bool) {
+    let input = fetch(
+        2, ',',
+    );
+    let mut ans = 0;
+
+    for s in input {
+        let s = s.replace(
+            '\n', "",
+        );
+        if s.is_empty() {
+            continue;
+        }
+        let split = s.split('-');
+        let first = split
+            .clone()
+            .next()
+            .unwrap()
+            .parse()
+            .unwrap();
+        let last = split
+            .clone()
+            .nth(1)
+            .unwrap()
+            .parse()
+            .unwrap();
+        ans += &Checker::new(
+            first, last,
+        )
+        .unwrap()
+        .parse(part2);
+    }
+    println!("{ans}");
+}
+
+pub fn part1() {
+    run(false);
+}
+
+pub fn part2() {
+    run(true);
+}