From 6fa33b4e3e8def13edf0ea731ce260cef4939df0 Mon Sep 17 00:00:00 2001
From: andrewlalis <andrewlalisofficial@gmail.com>
Date: Fri, 1 Dec 2023 10:21:40 -0500
Subject: [PATCH] Cleaned up my solution more.

---
 README.md        |  2 ++
 day_1/solution.d | 54 +++++++++++++++++++++---------------------------
 2 files changed, 25 insertions(+), 31 deletions(-)

diff --git a/README.md b/README.md
index 6924a1b..bc51641 100644
--- a/README.md
+++ b/README.md
@@ -3,3 +3,5 @@
 This repository has my solutions for this year's Advent of Code challenges. Each day's challenge will be placed into a directory named `day_N`, where `N` is the day of the challenge. Each day will have a solution program named `solution.*` (with the filetype depending on which programming language I used).
 
 For D programs, you can simply run them with `rdmd solution.d`.
+
+Note that I try and solve the problems as fast as possible, but then I go back and clean up my solution, so what you see isn't really my ugly first attempt.
diff --git a/day_1/solution.d b/day_1/solution.d
index 2060fc8..0ff17ea 100644
--- a/day_1/solution.d
+++ b/day_1/solution.d
@@ -5,21 +5,27 @@ import std.string : splitLines;
 import std.algorithm;
 import std.stdio;
 import std.uni : isNumber;
+import std.functional;
+
+/// Parses the first and last digits, using a function F to determine if and
+/// what digit is at a string at a particular index. F should return -1 if no
+/// digit exists.
+int parseDigits(int delegate(string, size_t) F)(string s) {
+    int a = -1, b = -1;
+    for (size_t i = 0; i < s.length; i++) {
+        int an = F(s, i);
+        int bn = F(s, s.length-i-1);
+        if (a == -1 && an != -1) a = an;
+        if (b == -1 && bn != -1) b = bn;
+        if (a != -1 && b != -1) break;
+    }
+    return a * 10 + b;
+}
 
 void part1() {
-    readText("part_1_input.txt")
-        .splitLines()
-        .map!((line) {
-            int a = -1, b = -1;
-            for (size_t i = 0; i < line.length; i++) {
-                if (a == -1 && isNumber(line[i])) a = line[i] - '0';
-                if (b == -1 && isNumber(line[$-i-1])) b = line[$-i-1] - '0';
-                if (a != -1 && b != -1) break;
-            }
-            return a * 10 + b;
-        })
-        .sum()
-        .writeln();
+    readText("part_1_input.txt").splitLines()
+        .map!(line => parseDigits!((s, i) => isNumber(s[i]) ? s[i] - '0' : -1)(line))
+        .sum().writeln();
 }
 
 void part2() {
@@ -27,28 +33,14 @@ void part2() {
         if (isNumber(s[idx])) return s[idx] - '0';
         const string[] words = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine"];
         static foreach (size_t i, string word; words) {
-            if (s.length - idx >= word.length && s[idx .. idx + word.length] == word) {
-                return cast(int) i + 1;
-            }
+            if (s.length - idx >= word.length && s[idx .. idx + word.length] == word) return cast(int) i + 1;
         }
         return -1;
     }
 
-    readText("part_2_input.txt")
-        .splitLines()
-        .map!((line) {
-            int a = -1, b = -1;
-            for (size_t i = 0; i < line.length; i++) {
-                int an = findDigit(line, i);
-                int bn = findDigit(line, line.length-i-1);
-                if (a == -1 && an != -1) a = an;
-                if (b == -1 && bn != -1) b = bn;
-                if (a != -1 && b != -1) break;
-            }
-            return a * 10 + b;
-        })
-        .sum()
-        .writeln();
+    readText("part_2_input.txt").splitLines()
+        .map!(line => parseDigits!((s, i) => findDigit(s, i))(line))
+        .sum().writeln();
 }
 
 void main() {