perf(11/2015): skip ambiguous letters during increment

Author: manhunto

readme.md

@@ -97,7 +97,7 @@
 | [Day 8: Matchsticks](src/solutions/year2015/day08.rs)                            |   ⭐⭐   |            0.052 |            0.129 |
 | [Day 9: All in a Single Night](src/solutions/year2015/day09.rs)                  |   ⭐⭐   |           34.320 |           34.850 |
 | [Day 10: Elves Look, Elves Say](src/solutions/year2015/day10.rs)                 |   ⭐⭐   |            2.099 |           32.258 |
-| [Day 11: Corporate Policy](src/solutions/year2015/day11.rs)                      |   ⭐⭐   |            0.543 |           19.202 |
+| [Day 11: Corporate Policy](src/solutions/year2015/day11.rs)                      |   ⭐⭐   |            0.543 |           14.384 |
 
 # TODO
 

src/solutions/year2015/day11.rs

@@ -72,8 +72,11 @@ impl<const N: usize> Password<N> {
                 i -= 1;
                 continue;
             } else {
-                //fixme: if current letter is ambiguous we can skip to the next (optimization)
-                chars[i] += 1;
+                if Self::is_letter_ambiguous(chars[i] + 1) {
+                    chars[i] += 2;
+                } else {
+                    chars[i] += 1;
+                }
                 break;
             }
         }
@@ -94,14 +97,18 @@ impl<const N: usize> Password<N> {
 
     fn not_contains_ambiguous_letters(&self) -> bool {
         for i in 0..N {
-            if self.chars[i] == b'i' || self.chars[i] == b'o' || self.chars[i] == b'l' {
+            if Self::is_letter_ambiguous(self.chars[i]) {
                 return false;
             }
         }
 
         true
     }
 
+    fn is_letter_ambiguous(char: u8) -> bool {
+        char == b'i' || char == b'o' || char == b'l'
+    }
+
     fn contains_nonoverlapping_two_pairs(&self) -> bool {
         let mut i = 0;
         let mut pairs = 0;