Day 2 aoc in progress

advent_of_code/2025/2/src/main.rs

@@ -0,0 +1,123 @@
+use std::cmp::{max, min};
+
+fn parse_input(input: &str) -> Vec<(i64, i64)> {
+    let line = input.lines().next().unwrap();
+
+    line.split(",")
+        .map(|id_range| {
+            let mut id_range_iter = id_range.split("-");
+
+            (
+                id_range_iter.next().unwrap().parse::<i64>().unwrap(),
+                id_range_iter.next().unwrap().parse::<i64>().unwrap(),
+            )
+        })
+        .collect()
+}
+
+fn solve_1(input: &str) -> i64 {
+    let ranges = parse_input(input);
+
+    let mut result = 0;
+
+    for range in ranges {
+        let min_length = range.0.to_string().len();
+        let max_length = range.1.to_string().len();
+
+        for range_length in min_length..=max_length {
+            if range_length % 2 == 0 {
+                let mut range_start = max(range.0, 10_i64.pow(range_length as u32 - 1));
+                let mut range_end = min(range.1, 10_i64.pow(range_length as u32) - 1);
+
+                let start_halves = range_start.to_string();
+                let start_halves = start_halves.split_at(range_length / 2);
+                let (start_first_half, start_second_half) = (
+                    start_halves.0.parse::<i64>().unwrap(),
+                    start_halves.1.parse::<i64>().unwrap(),
+                );
+
+                if start_first_half < start_second_half {
+                    range_start = start_first_half + 1;
+                } else {
+                    range_start = start_first_half;
+                }
+
+                let end_halves = range_end.to_string();
+                let end_halves = end_halves.split_at(range_length / 2);
+                let (end_first_half, end_second_half) = (
+                    end_halves.0.parse::<i64>().unwrap(),
+                    end_halves.1.parse::<i64>().unwrap(),
+                );
+
+                if end_first_half > end_second_half {
+                    range_end = end_first_half - 1;
+                } else {
+                    range_end = end_first_half;
+                }
+
+                for x in range_start..=range_end {
+                    result += x * 10_i64.pow(range_length as u32 / 2) + x;
+                }
+            }
+        }
+    }
+
+    result
+}
+
+fn get_factors(n: i64) -> Vec<i64> {
+    // Naive implementation, not counting n itself, but counting 1 always
+}
+
+fn solve_2(input: &str) -> i64 {
+    let ranges = parse_input(input);
+
+    let mut result = 0;
+
+    for range in ranges {
+        let min_length = range.0.to_string().len();
+        let max_length = range.1.to_string().len();
+
+        for range_length in min_length..=max_length {
+            let range_start = max(range.0, 10_i64.pow(range_length as u32 - 1));
+            let range_end = min(range.1, 10_i64.pow(range_length as u32) - 1);
+
+            let factors = get_factors(range_length);
+
+            for factor in factors {
+
+            }
+        }
+    }
+
+    result
+}
+
+fn main() {
+    println!("Hello, this is Patrick!");
+
+    let input = include_str!("../input.txt");
+
+    let result_1 = solve_1(input);
+    println!("Sum of false ids: {}", result_1);
+
+    let result_2 = solve_2(input);
+    println!("{}", result_2);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let test_input = include_str!("../test.txt");
+        assert_eq!(solve_1(test_input), 1227775554);
+    }
+
+    #[test]
+    fn test_2() {
+        let test_input = include_str!("../test.txt");
+        assert_eq!(solve_2(test_input), 4174379265);
+    }
+}