Day 3 Part 1... WOW!!!

src/solutions/day03.rs

@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use super::Solution;
 
 pub struct Day03 {}
@@ -5,9 +7,17 @@ pub struct Day03 {}
 impl Solution for Day03 {
     fn part1(
         &self,
-        _input: &mut Vec<String>,
+        input: &mut Vec<String>,
     ) -> Result<Box<dyn std::fmt::Display>, Box<dyn std::error::Error>> {
-        Ok(Box::new("Ready"))
+        // Get data into a byte array
+        let lines = input.iter().map(|s| s.as_bytes()).collect::<Vec<_>>();
+        let mut symbols: HashMap<(usize, usize, char), Vec<usize>> = HashMap::new();
+
+        // Get the valid numbers from the input
+        self.map_valid_nums(&lines, &mut symbols)?;
+
+        let ans: usize = symbols.values().flat_map(|v| v).sum();
+        Ok(Box::new(ans))
     }
 
     fn part2(
@@ -22,7 +32,60 @@ impl Solution for Day03 {
     }
 }
 
-impl Day03 {}
+impl Day03 {
+    fn map_valid_nums(
+        &self,
+        lines: &Vec<&[u8]>,
+        symbols: &mut HashMap<(usize, usize, char), Vec<usize>>,
+    ) -> Result<(), Box<dyn std::error::Error>> {
+        for (i, line) in lines.iter().enumerate() {
+            let mut c = 0;
+
+            while c < line.len() {
+                let (start, mut symbol) = (c, None);
+
+                while c < line.len() && line[c].is_ascii_digit() {
+                    // Coordinate deltas for adjacent checks
+                    for (drow, dcol) in [
+                        (-1, -1),
+                        (-1, 0),
+                        (-1, 1),
+                        (0, -1),
+                        (0, 1),
+                        (1, -1),
+                        (1, 0),
+                        (1, 1),
+                    ] {
+                        let (row, column) =
+                            ((i as i32 + drow) as usize, (c as i32 + dcol) as usize);
+
+                        // Get symbol at adjacent row
+                        let Some(&s) = lines.get(row).and_then(|l| l.get(column)) else {
+                            continue;
+                        };
+
+                        if s != b'.' && !s.is_ascii_digit() {
+                            symbol = Some((column, row, s as char));
+                            break;
+                        }
+                    }
+                    c += 1;
+                }
+
+                if start < c {
+                    if let Some(symbol) = symbol {
+                        let num = line[start..c]
+                            .iter()
+                            .fold(0, |n, c| n * 10 + (c - b'0') as usize);
+                        symbols.entry(symbol).or_insert(Vec::new()).push(num)
+                    }
+                }
+                c += 1;
+            }
+        }
+        Ok(())
+    }
+}
 
 /// Test from puzzle input
 #[cfg(test)]
@@ -44,7 +107,7 @@ mod test {
             .unwrap()
             .to_string();
 
-        assert_eq!(answer, "Ready");
+        assert_eq!(answer, "4361");
     }
 
     #[test]