From 4d95eabd78c65c9144e9d263a51e18be119415e1 Mon Sep 17 00:00:00 2001
From: Kees van Kempen <git@keesvankempen.nl>
Date: Sat, 2 Dec 2023 23:12:20 +0100
Subject: [PATCH] 2023(1): My god, here is some WET code

---
 2023/day/1/main.rs | 83 +++++++++++++++++++++++++++-------------------
 1 file changed, 49 insertions(+), 34 deletions(-)

diff --git a/2023/day/1/main.rs b/2023/day/1/main.rs
index 25640ae..5d87dcd 100644
--- a/2023/day/1/main.rs
+++ b/2023/day/1/main.rs
@@ -1,6 +1,7 @@
 use std::fs::File;
 use std::io::{self, BufRead};
 use std::path::Path;
+use std::collections::HashMap;
 
 fn main() {
 	let mut sum = 0;
@@ -9,30 +10,14 @@ fn main() {
 	if let Ok(lines) = read_lines("./input") {
 		for line in lines {
 			if let Ok(text) = line {
-				// TODO: Please us something like a collection instead of
-				// hardcoding every replacement.
-				let sanitext = text
-					.replace("one",   "1")
-					.replace("two",	  "2")
-					.replace("three", "3")
-					.replace("four",  "4")
-					.replace("five",  "5")
-					.replace("six",   "6")
-					.replace("seven", "7")
-					.replace("eight", "8")
-					.replace("nine",  "9")
-					;
-				// DEBUG:
-				println!(
-					"{} => {} yields {} + {} = {}",
-					text,
-					sanitext,
-					first_digit(&sanitext),
-					last_digit(&sanitext),
-					first_digit(&sanitext) + last_digit(&sanitext)
-				);
-				sum = sum + first_digit(&sanitext);
-				mus = mus + last_digit(&sanitext);
+				//println!(
+				//	"{} yields {:?} + {:?}",
+				//	text,
+				//	first_digit(&text),
+				//	last_digit(&text),
+				//);
+				sum = sum + first_digit(&text).unwrap_or(0);
+				mus = mus + last_digit(&text).unwrap_or(0);
 			} else {
 				println!("Error on line \"{:?}\"", line);
 			}
@@ -42,20 +27,50 @@ fn main() {
 	println!("{}", 10*sum + mus);
 }
 
-// TODO: Switch to Option(i32) to allow not having a digit in text <https://doc.rust-lang.org/std/option/>.
-fn first_digit(text: &String) -> i32 {
-	for c in text.chars() {
-		if c.is_digit(10) {
-			return c.to_digit(10).unwrap() as i32;
+const DIGITSTABLE: [(&str, u32); 18]= [
+	("1", 1), ("one",   1),
+	("2", 2), ("two",   2),
+	("3", 3), ("three", 3),
+	("4", 4), ("four",  4),
+	("5", 5), ("five",  5),
+	("6", 6), ("six",   6),
+	("7", 7), ("seven", 7),
+	("8", 8), ("eight", 8),
+	("9", 9), ("nine",  9),
+];
+
+fn first_digit(text: &String) -> Option<u32> {
+	let digits = HashMap::from(DIGITSTABLE);
+
+	let mut hit = false;
+	let mut first_digit: &u32 = &0;
+	let mut first_index: usize = 0;
+	for (needle, digit) in &digits {
+		let index = text.find(needle);
+		if index.is_some() && (!hit || index.unwrap() < first_index) {
+			hit = true;
+			first_digit = digit;
+			first_index = index.unwrap();
 		}
 	}
-	// TODO: What if there is no digit?
-	0
+	if hit { Some(*first_digit) } else { None }
 }
 
-fn last_digit(text: &String) -> i32 {
-	let txet = &mut text.chars().rev().collect();
-	first_digit(txet)
+fn last_digit(text: &String) -> Option<u32> {
+	let digits = HashMap::from(DIGITSTABLE);
+
+	let mut hit = false;
+	let mut last_digit: &u32 = &0;
+	let mut last_index: usize = 0;
+	for (needle, digit) in &digits {
+		let index = text.rfind(needle);
+		if index.is_some() && (!hit || index.unwrap() > last_index) {
+			hit = true;
+			last_digit = digit;
+			last_index = index.unwrap();
+		}
+	}
+	if hit { Some(*last_digit) } else { None }
 }
 
 fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>