diff --git a/src/day03.rs b/src/day03.rs
index e59c127..bfa1d14 100644
--- a/src/day03.rs
+++ b/src/day03.rs
@@ -1,4 +1,4 @@
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 
 use aoc_runner_derive::{aoc, aoc_generator};
 use nom::{Finish, IResult};
@@ -15,14 +15,14 @@ fn input_generator(input: &str) -> Vec<String> {
 
 #[aoc(day3, part1)]
 fn part1(input: &[String]) -> u32 {
-    let mut symbol_neighbors = HashSet::new();
-    for (row, line) in input.iter().enumerate() {
-        for (col, ch) in line.chars().enumerate() {
-            if !ch.is_ascii_digit() && ch != '.' {
-                symbol_neighbors.extend(GridIndex::new(col, row).neighbors());
-            }
-        }
-    }
+    let symbol_neighbors = input
+        .iter()
+        .enumerate()
+        .flat_map(|(row, line)| {
+            line.match_indices(|ch: char| !ch.is_ascii_digit() && ch != '.')
+                .flat_map(move |(col, _)| GridIndex::new(col, row).neighbors())
+        })
+        .collect::<Vec<_>>();
     let mut part_sum = 0;
     for (row, line) in input.iter().enumerate() {
         let mut col: usize = 0;
@@ -32,8 +32,8 @@ fn part1(input: &[String]) -> u32 {
                 let rest = &line[col..];
                 let (rem, num) = parse_num(rest).finish().unwrap();
                 let num_len = rest.len() - rem.len();
-                for i in 0..num_len {
-                    if symbol_neighbors.contains(&GridIndex::new(col + i, row)) {
+                for col in col..(col + num_len) {                    
+                    if symbol_neighbors.contains(&GridIndex::new(col, row)) {
                         part_sum += num;
                         break;
                     }
@@ -49,14 +49,14 @@ fn part1(input: &[String]) -> u32 {
 
 #[aoc(day3, part2)]
 fn part2(input: &[String]) -> u32 {
-    let mut gear_locs = Vec::new();
-    for (row, line) in input.iter().enumerate() {
-        for (col, ch) in line.chars().enumerate() {
-            if ch == '*' {
-                gear_locs.push(GridIndex::new(col, row));
-            }
-        }
-    }
+    let gear_locs = input
+        .iter()
+        .enumerate()
+        .flat_map(|(row, line)| {
+            line.match_indices('*')
+                .map(move |(col, _)| GridIndex::new(col, row))
+        })
+        .collect::<Vec<_>>();
     let mut gear_neighbor_numbers = HashMap::<usize, Vec<u32>>::new();
     for (row, line) in input.iter().enumerate() {
         let mut col: usize = 0;
@@ -81,12 +81,9 @@ fn part2(input: &[String]) -> u32 {
             }
         }
     }
-    let mut gear_ratio_sum = 0;
-    for (_, number_neighbors) in gear_neighbor_numbers.iter() {
-        if number_neighbors.len() != 2 {
-            continue;
-        }
-        gear_ratio_sum += number_neighbors[0] * number_neighbors[1];
-    }
-    gear_ratio_sum
+    gear_neighbor_numbers
+        .values()
+        .filter(|x| x.len() == 2)
+        .map(|x| x[0] * x[1])
+        .sum()
 }