Implement day23 part 1.

2018/src/day23.rs

@@ -1,19 +1,61 @@
 use std::io::Read;
 
 use common::Solution;
+use regex::Regex;
+use std::io::BufReader;
+use std::io::BufRead;
+use common::Point;
+use std::collections::VecDeque;
+use std::collections::HashSet;
+use std::collections::HashMap;
+
+type Coordinate = (i64, i64, i64);
 
 #[derive(Default)]
-pub struct Day23 {}
+pub struct Day23 {
+    bots: Vec<(i64, Coordinate)>
+}
 
 impl Day23 {
     pub fn new() -> Self {
         Default::default()
     }
+
+    fn read_input(&mut self, input: &mut Read) {
+        let matcher = Regex::new(r"-?\d+").unwrap();
+        let reader = BufReader::new(input);
+
+        for line in reader.lines() {
+            let line = line.unwrap();
+
+            let mut ints = [0i64;4];
+            for (c, i) in matcher.find_iter(&line).zip(ints.iter_mut()) {
+                *i = c.as_str().parse().unwrap();
+            }
+
+            let pos = (ints[0], ints[1], ints[2]);
+
+            self.bots.push((ints[3], pos));
+        }
+    }
+
+    fn in_range(&self, pos: Coordinate) -> usize {
+        self.bots.iter()
+            .filter(|&&(range, other)| other.manhattan(pos) <= range)
+            .count()
+    }
 }
 
 impl Solution for Day23 {
-    fn part1(&mut self, _input: &mut Read) -> String {
-        unimplemented!()
+    fn part1(&mut self, input: &mut Read) -> String {
+        self.read_input(input);
+        self.bots.sort_unstable();
+        let (best_range, best_pos) = *self.bots.last().unwrap();
+
+        let result = self.bots.iter().filter(|(_, pos)| pos.manhattan(best_pos) <= best_range)
+            .count();
+
+        result.to_string()
     }
 
     fn part2(&mut self, _input: &mut Read) -> String {
@@ -22,4 +64,15 @@ impl Solution for Day23 {
 }
 
 #[cfg(test)]
-mod tests {}
+mod tests {
+    use day23::Day23;
+    use common::Solution;
+
+    const SAMPLE1_INPUT: &[u8] = include_bytes!("samples/23.1.txt");
+
+    #[test]
+    fn sample_part1() {
+        let mut instance = Day23::new();
+        assert_eq!("7", instance.part1(&mut SAMPLE1_INPUT));
+    }
+}