Day 5 - Part 1

Signed-off-by: Anthony Oteri <anthony.oteri@gmail.com>

day-05/src/main.rs

@@ -0,0 +1,132 @@
+use std::collections::BTreeMap;
+
+const SOIL: &'static str = "seed-to-soil";
+const FERT: &'static str = "soil-to-fertilizer";
+const WATER: &'static str = "fertilizer-to-water";
+const LIGHT: &'static str = "water-to-light";
+const TEMP: &'static str = "light-to-temperature";
+const HUMIDITY: &'static str = "temperature-to-humidity";
+const LOC: &'static str = "humidity-to-location";
+
+fn extract_seeds(input: &str) -> Vec<usize> {
+    let line = input.lines().nth(0).unwrap();
+    let (_, values) = line.split_once(':').unwrap();
+    values
+        .split_whitespace()
+        .map(|s| s.parse::<usize>().unwrap())
+        .collect()
+}
+
+fn extract_map_lines(input: &str, key: &'static str) -> Vec<String> {
+    let mut lines: Vec<String> = input.lines().map(String::from).collect();
+
+    let start_idx = lines.iter().position(|line| line.starts_with(key)).unwrap();
+    lines.drain(..=start_idx);
+
+    if let Some(end_idx) = lines.iter().position(|line| line.is_empty()) {
+        lines.drain(end_idx..);
+    }
+
+    lines
+}
+
+fn lookup(input: &str, source: usize, map: &'static str) -> usize {
+    let map_lines = extract_map_lines(input, map);
+
+    for line in map_lines {
+        let values: Vec<usize> = line
+            .split_whitespace()
+            .map(|s| s.parse::<usize>().unwrap())
+            .collect();
+
+        let dest_range_start = values[0];
+        let source_range_start = values[1];
+        let range_length = values[2];
+
+        let source_range_end = source_range_start + range_length;
+        if source >= source_range_start && source < source_range_end {
+            return dest_range_start + (source - source_range_start);
+        }
+    }
+
+    source
+}
+
+fn lookup_location(input: &str, seed: usize) -> usize {
+    dbg!(&seed);
+    let soil = lookup(input, seed, SOIL);
+    dbg!(&soil);
+
+    let fert = lookup(input, soil, FERT);
+    dbg!(&fert);
+    let water = lookup(input, fert, WATER);
+    dbg!(&water);
+    let light = lookup(input, water, LIGHT);
+    dbg!(&light);
+    let temp = lookup(input, light, TEMP);
+    dbg!(&temp);
+    let humidity = lookup(input, temp, HUMIDITY);
+    dbg!(&humidity);
+    let loc = lookup(input, humidity, LOC);
+    dbg!(&loc);
+
+    loc
+}
+
+fn part_1(input: &str) -> u32 {
+    let seeds = extract_seeds(input);
+    let mut locs = Vec::new();
+    for seed in seeds {
+        locs.push(lookup_location(input, seed));
+    }
+    locs.iter().min().unwrap().clone() as u32
+}
+
+fn main() {
+    let input = include_str!("../input.txt");
+    println!("Part 1: {}", part_1(input));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_extract_seeds() {
+        let input = include_str!("../test-input.txt");
+        let seeds = extract_seeds(input);
+        assert_eq!(seeds, vec![79, 14, 55, 13]);
+    }
+
+    #[test]
+    fn test_extract_map() {
+        let input = include_str!("../test-input.txt");
+        let lines = extract_map_lines(input, "seed-to-soil");
+        assert_eq!(lines, vec!["50 98 2", "52 50 48"]);
+    }
+
+    #[test]
+    fn test_lookup_location() {
+        let input = include_str!("../test-input.txt");
+
+        assert_eq!(lookup_location(input, 79), 82);
+        assert_eq!(lookup_location(input, 14), 43);
+        assert_eq!(lookup_location(input, 55), 86);
+        assert_eq!(lookup_location(input, 13), 35);
+    }
+
+    #[test]
+    fn test_lookup() {
+        let input = include_str!("../test-input.txt");
+        assert_eq!(lookup(input, 79, SOIL), 81);
+        assert_eq!(lookup(input, 14, SOIL), 14);
+        assert_eq!(lookup(input, 55, SOIL), 57);
+        assert_eq!(lookup(input, 13, SOIL), 13);
+    }
+
+    #[test]
+    fn test_part_1() {
+        let input = include_str!("../test-input.txt");
+        assert_eq!(part_1(input), 35);
+    }
+}