Day 1 part 2.

src/main.rs

@@ -1,6 +1,6 @@
 use std::io;
 
-fn main() {
+fn get_calibration_digits() -> u32 {
   let mut buffer = String::new();
   let mut sum = 0;
   while io::stdin().read_line(&mut buffer).unwrap() > 0 {
@@ -8,5 +8,95 @@ fn main() {
     sum += nums.first().unwrap() * 10 + nums.last().unwrap();
     buffer = String::new();
   }
-  println!("Sum: {}", sum);
+  sum
+}
+
+const NUMBERS: [&'static str; 9] = [
+  "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
+];
+
+enum SearchDir {
+  First,
+  Last,
+}
+
+fn get_digit(line: &String, dir: SearchDir) -> u32 {
+  let mut first: usize = 0;
+  let mut index: Option<usize> = None;
+  for n in 1..=9 {
+    let f = match &dir {
+      SearchDir::First => line.find(&n.to_string()),
+      SearchDir::Last => line.rfind(&n.to_string()),
+    };
+    if f == None {
+      continue;
+    }
+    let found = f.unwrap();
+    match index {
+      None => {
+        index = f;
+        first = n;
+      }
+      Some(i) => match &dir {
+        SearchDir::First => {
+          if found < i {
+            index = f;
+            first = n;
+          }
+        }
+        SearchDir::Last => {
+          if found > i {
+            index = f;
+            first = n;
+          }
+        }
+      },
+    }
+  }
+  for (num, num_str) in NUMBERS.iter().enumerate() {
+    let f = match &dir {
+      SearchDir::First => line.find(num_str),
+      SearchDir::Last => line.rfind(num_str),
+    };
+    if f == None {
+      continue;
+    }
+    let found = f.unwrap();
+    match index {
+      None => {
+        index = f;
+        first = num + 1;
+      }
+      Some(i) => match &dir {
+        SearchDir::First => {
+          if found < i {
+            index = f;
+            first = num + 1;
+          }
+        }
+        SearchDir::Last => {
+          if found > i {
+            index = f;
+            first = num + 1;
+          }
+        }
+      },
+    }
+  }
+  first.try_into().unwrap()
+}
+
+fn get_calibration_digits_alnum() -> u32 {
+  let mut buffer = String::new();
+  let mut sum = 0;
+  while io::stdin().read_line(&mut buffer).unwrap() > 0 {
+    let val = (get_digit(&buffer, SearchDir::First) * 10) + get_digit(&buffer, SearchDir::Last);
+    sum += val;
+    buffer = String::new();
+  }
+  sum
+}
+
+fn main() {
+  println!("Sum: {}", get_calibration_digits_alnum());
 }