1 files changed, 86 insertions, 0 deletions
diff --git a/2023/day-01/src/bin/part2.rs b/2023/day-01/src/bin/part2.rs
new file mode 100644
index 0000000..5185b76
--- /dev/null
+++ b/2023/day-01/src/bin/part2.rs
@@ -0,0 +1,86 @@
+use std::collections::HashMap;
+
+fn main() {
+    let input = include_str!("./input.txt");
+    let output: i32 = input.lines().map(process_line).sum();
+    println!("Result {}", output);
+}
+
+/// Return the position of `needle` in `string`
+fn find_ocurrences<'a>(string: &'a str, needle: &str) -> Vec<(usize, &'a str)> {
+    string.match_indices(needle).collect()
+}
+
+fn find_min<'a>(matches: &[(usize, &'a str)]) -> (usize, &'a str) {
+    let (position, word) = matches.iter().min_by(|(x,_), (y, _)| {
+	x.cmp(y)
+    }).unwrap();
+
+    (*position, word)
+}
+
+#[test]
+fn test_find_min_1() {
+    let input = vec!((1, "eight"), (2, "eight"), (3, "2"));
+    assert_eq!(find_min(&input), (1, "eight"));
+}
+
+#[test]
+fn test_find_min_2() {
+    let input = vec!((4, "eight"), (5, "eight"), (3, "2"));
+    assert_eq!(find_min(&input), (3, "2"));
+}
+
+fn find_max<'a>(matches: &[(usize, &'a str)]) -> (usize, &'a str) {
+    let (position, word) = matches.iter().min_by(|(x,_), (y, _)| {
+	y.cmp(x)
+    }).unwrap();
+
+    (*position, word)
+}
+
+/// Return the first and last number on `s`
+fn process_line(s: &str) -> i32 {
+    let mapping: HashMap<&str, i32> = HashMap::from([
+	("one", 1), ("two", 2), ("three", 3),
+	("four", 4), ("five", 5), ("six", 6),
+	("seven", 7), ("eight", 8), ("nine", 9),
+	("1", 1), ("2", 2), ("3", 3), ("4", 4), ("5", 5),
+	("6", 6), ("7", 7), ("8", 8), ("9", 9),
+    ]);
+
+    let matches = mapping.iter().map(|(k, _)| {
+	find_ocurrences(s, k)
+    }).collect::<Vec<_>>().concat();
+    let (_, min_number) = find_min(&matches);
+    let (_, max_number) = find_max(&matches);
+
+    (mapping[min_number] * 10) + mapping[max_number]
+}
+
+#[test]
+fn simple_input() {
+    let string = "onetwo";
+    assert_eq!(process_line(string), 12);
+}
+
+#[test]
+fn overlap_input() {
+    let string = "oneight";
+    assert_eq!(process_line(string), 18);
+}
+
+#[test]
+fn example() {
+    let string = "two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen";
+
+    let result: Vec<i32> = string.lines().map(process_line).collect();
+
+    assert_eq!(result, &[29, 83, 13, 24, 42, 14, 76]);
+}