Add solution for "Day 6: Trash Compactor", part 2

src/solvers/trash_compactor.rs

@@ -1,11 +1,74 @@
 use crate::solvers::Solver;
-use grid::*;
+use grid::Grid;
 use std::io::BufRead;
 
 pub struct TrashCompactor {}
 
 impl TrashCompactor {
     const NUMBER_SPLIT_CHAR: char = ' ';
+    const SUM_SIGN: &'static str = "+";
+    const PRODUCT_SIGN: &'static str = "*";
+
+    fn add_row_layout_line(line: &str, numbers: &mut Grid<u64>) {
+        let v: Vec<u64> = line
+            .split(Self::NUMBER_SPLIT_CHAR)
+            .filter_map(|s| {
+                if s.is_empty() {
+                    None
+                } else {
+                    Some(s.parse().unwrap())
+                }
+            })
+            .collect();
+        numbers.push_row(v);
+    }
+
+    fn row_layout_calculation(numbers: &Grid<u64>, signs: &Vec<&str>) -> u64 {
+        let mut result = 0;
+        for (i, sign) in signs.iter().enumerate() {
+            match *sign {
+                Self::SUM_SIGN => result += numbers.iter_col(i).sum::<u64>(),
+                Self::PRODUCT_SIGN => result += numbers.iter_col(i).product::<u64>(),
+                _ => {}
+            }
+        }
+        result
+    }
+
+    fn add_column_layout_line(line: &str, numbers: &mut Vec<u64>) {
+        let add = line
+            .bytes()
+            .map(|c| if c.is_ascii_digit() { c - b'0' } else { 0 })
+            .collect::<Vec<u8>>();
+        if numbers.len() < 1 {
+            *numbers = vec![0; add.len()];
+        }
+        for (i, n) in numbers.iter_mut().enumerate() {
+            if add[i] > 0 {
+                *n = *n * 10 + add[i] as u64;
+            }
+        }
+    }
+
+    fn column_layout_calculation(numbers: &Vec<u64>, signs: &Vec<&str>) -> u64 {
+        let mut result = 0;
+        let mut it = numbers.iter();
+        for sign in signs {
+            let block_it = it.by_ref().take_while(|&&n| n > 0);
+            match *sign {
+                Self::SUM_SIGN => result += block_it.sum::<u64>(),
+                Self::PRODUCT_SIGN => result += block_it.product::<u64>(),
+                _ => {}
+            }
+        }
+        result
+    }
+
+    fn signs(line: &str) -> Vec<&str> {
+        line.split(Self::NUMBER_SPLIT_CHAR)
+            .filter(|s| !s.is_empty())
+            .collect()
+    }
 }
 
 impl Solver for TrashCompactor {
@@ -13,26 +76,21 @@ impl Solver for TrashCompactor {
     const PUZZLE_NAME: &'static str = "Trash Compactor";
 
     fn process_data<R: BufRead>(&self, reader: R) -> (u64, u64) {
-        let mut part1 = 0;
-        let mut grid = Grid::new(0, 0);
+        let mut row_layout_result = 0;
+        let mut column_layout_result = 0;
+        let mut row_layout_numbers = Grid::new(0, 0);
+        let mut column_layout_numbers = Vec::new();
         for line in reader.lines().map_while(Result::ok) {
-            let v: Vec<&str> = line
-                .split(Self::NUMBER_SPLIT_CHAR)
-                .filter(|s| !s.is_empty())
-                .collect();
-            match v[0].parse::<u32>() {
-                Ok(_) => grid.push_row(v.iter().map(|n| n.parse::<u64>().unwrap()).collect()),
-                Err(_) => {
-                    for (i, sign) in v.iter().enumerate() {
-                        if *sign == "+" {
-                            part1 += grid.iter_col(i).sum::<u64>();
-                        } else {
-                            part1 += grid.iter_col(i).product::<u64>();
-                        }
-                    }
-                }
+            if line.as_bytes()[0].is_ascii_digit() || line.as_bytes()[0].is_ascii_whitespace() {
+                Self::add_row_layout_line(&line, &mut row_layout_numbers);
+                Self::add_column_layout_line(&line, &mut column_layout_numbers);
+            } else {
+                let signs = Self::signs(&line);
+                row_layout_result = Self::row_layout_calculation(&row_layout_numbers, &signs);
+                column_layout_result =
+                    Self::column_layout_calculation(&column_layout_numbers, &signs);
             }
         }
-        (part1, 0)
+        (row_layout_result, column_layout_result)
     }
 }