Collect into vec for nicer vectorization

2022/src/day01.rs

@@ -2,7 +2,6 @@ use std::ops::Add;
 
 use anyhow::Result;
 use nom::character::complete::newline;
-use nom::combinator::opt;
 use nom::multi::separated_list0;
 use nom::sequence::terminated;
 use nom::IResult;
@@ -14,13 +13,9 @@ fn parse_elf(input: &[u8]) -> IResult<&[u8], i32> {
     reduce_many1(terminated(nom::character::complete::i32, newline), Add::add)(input)
 }
 
-fn parse_max(input: &[u8]) -> IResult<&[u8], i32> {
-    reduce_many1(terminated(parse_elf, opt(newline)), Ord::max)(input)
-}
-
 pub fn part1(input: &[u8]) -> Result<String> {
-    let result = parse_input(input, parse_max)?.to_string();
-    Ok(result)
+    let elves = parse_input(input, parse_elf_list)?;
+    Ok(elves.into_iter().fold(0, Ord::max).to_string())
 }
 
 fn parse_elf_list(input: &[u8]) -> IResult<&[u8], Vec<i32>> {

2022/src/day02.rs

@@ -1,15 +1,12 @@
-use std::ops::Add;
-
 use anyhow::Result;
 use nom::character::complete::newline;
-use nom::combinator::map;
 use nom::combinator::map_res;
+use nom::multi::many0;
 use nom::sequence::separated_pair;
 use nom::sequence::terminated;
 use nom::IResult;
 
 use crate::common::parse_input;
-use crate::common::reduce_many1;
 
 #[derive(Copy, Clone, Eq, PartialEq)]
 enum Rps {
@@ -73,7 +70,7 @@ impl TryFrom<u8> for Rps {
     }
 }
 
-fn parse_line(input: &[u8]) -> IResult<&[u8], (Rps, Rps)> {
+fn parse_plan(input: &[u8]) -> IResult<&[u8], Vec<(Rps, Rps)>> {
     fn parse_rps(input: &[u8]) -> IResult<&[u8], Rps> {
         // Note: alpha1 also sort of works but is significantly slower
         map_res(nom::bytes::complete::take(1usize), |v: &[u8]| {
@@ -81,34 +78,33 @@ fn parse_line(input: &[u8]) -> IResult<&[u8], (Rps, Rps)> {
         })(input)
     }
 
-    terminated(
-        separated_pair(parse_rps, nom::character::complete::char(' '), parse_rps),
-        newline,
-    )(input)
+    fn parse_line(input: &[u8]) -> IResult<&[u8], (Rps, Rps)> {
+        separated_pair(parse_rps, nom::character::complete::char(' '), parse_rps)(input)
+    }
+
+    many0(terminated(parse_line, newline))(input)
 }
 
 pub fn part1(input: &[u8]) -> Result<String> {
-    parse_input(
-        input,
-        reduce_many1(
-            map(parse_line, |(them, us)| us.score() + us.score_against(them)),
-            Add::add,
-        ),
-    )
-    .map(|sum| sum.to_string())
+    let plan = parse_input(input, parse_plan)?;
+
+    let result: u32 = plan
+        .into_iter()
+        .map(|(them, us)| us.score() + us.score_against(them))
+        .sum();
+
+    Ok(result.to_string())
 }
 
 pub fn part2(input: &[u8]) -> Result<String> {
-    parse_input(
-        input,
-        reduce_many1(
-            map(parse_line, |(them, us)| {
-                us.score_result() + us.needed(them).score()
-            }),
-            Add::add,
-        ),
-    )
-    .map(|sum| sum.to_string())
+    let plan = parse_input(input, parse_plan)?;
+
+    let result: u32 = plan
+        .into_iter()
+        .map(|(them, us)| us.score_result() + us.needed(them).score())
+        .sum();
+
+    Ok(result.to_string())
 }
 
 #[cfg(test)]