From 334fe1043e0a4439c25a2f6bc3b03b2d297d6baa Mon Sep 17 00:00:00 2001
From: EFanZh <efanzh@gmail.com>
Date: Thu, 14 Sep 2023 23:50:44 +0800
Subject: [PATCH] Add problem 1839: Longest Substring Of All Vowels in Order

---
 src/lib.rs                                    |   1 +
 .../mod.rs                                    |  28 +++++
 .../state_machine.rs                          | 118 ++++++++++++++++++
 3 files changed, 147 insertions(+)
 create mode 100644 src/problem_1839_longest_substring_of_all_vowels_in_order/mod.rs
 create mode 100644 src/problem_1839_longest_substring_of_all_vowels_in_order/state_machine.rs

diff --git a/src/lib.rs b/src/lib.rs
index 9816d6c9..78ff1858 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1415,6 +1415,7 @@ pub mod problem_1827_minimum_operations_to_make_the_array_increasing;
 pub mod problem_1832_check_if_the_sentence_is_pangram;
 pub mod problem_1833_maximum_ice_cream_bars;
 pub mod problem_1837_sum_of_digits_in_base_k;
+pub mod problem_1839_longest_substring_of_all_vowels_in_order;
 
 #[cfg(test)]
 mod test_utilities;
diff --git a/src/problem_1839_longest_substring_of_all_vowels_in_order/mod.rs b/src/problem_1839_longest_substring_of_all_vowels_in_order/mod.rs
new file mode 100644
index 00000000..bc64e7a3
--- /dev/null
+++ b/src/problem_1839_longest_substring_of_all_vowels_in_order/mod.rs
@@ -0,0 +1,28 @@
+pub mod state_machine;
+
+pub trait Solution {
+    fn longest_beautiful_substring(word: String) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            ("aeiaaioaaaaeiiiiouuuooaauuaeiu", 13),
+            ("aeeeiiiioooauuuaeiou", 5),
+            ("a", 0),
+            ("iuaoeieaeeaeeiouueae", 7),
+            ("eauoiouieaaoueiuaieoeauoiaueoiaeoiuieuaoiaeouiaueo", 0),
+            ("aeuaeiiouoeiaeiiiii", 6),
+            ("aeio", 0),
+            ("aeioe", 0),
+            ("aeioua", 5),
+        ];
+
+        for (word, expected) in test_cases {
+            assert_eq!(S::longest_beautiful_substring(word.to_string()), expected);
+        }
+    }
+}
diff --git a/src/problem_1839_longest_substring_of_all_vowels_in_order/state_machine.rs b/src/problem_1839_longest_substring_of_all_vowels_in_order/state_machine.rs
new file mode 100644
index 00000000..a28c7785
--- /dev/null
+++ b/src/problem_1839_longest_substring_of_all_vowels_in_order/state_machine.rs
@@ -0,0 +1,118 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn longest_beautiful_substring(word: String) -> i32 {
+        let mut result = 0;
+        let mut iter = word.bytes();
+
+        'outer: while let Some(c) = iter.next() {
+            if c != b'a' {
+                continue;
+            }
+
+            // Start.
+
+            'start: loop {
+                let mut length = 1;
+
+                // a.
+
+                loop {
+                    match iter.next() {
+                        None => break 'outer,
+                        Some(b'a') => length += 1,
+                        Some(b'e') => break,
+                        Some(_) => continue 'outer,
+                    }
+                }
+
+                length += 1;
+
+                // e.
+
+                loop {
+                    match iter.next() {
+                        None => break 'outer,
+                        Some(b'a') => continue 'start,
+                        Some(b'e') => length += 1,
+                        Some(b'i') => break,
+                        Some(_) => continue 'outer,
+                    }
+                }
+
+                length += 1;
+
+                // i.
+
+                loop {
+                    match iter.next() {
+                        None => break 'outer,
+                        Some(b'a') => continue 'start,
+                        Some(b'i') => length += 1,
+                        Some(b'o') => break,
+                        Some(_) => continue 'outer,
+                    }
+                }
+
+                length += 1;
+
+                // o.
+
+                loop {
+                    match iter.next() {
+                        None => break 'outer,
+                        Some(b'a') => continue 'start,
+                        Some(b'o') => length += 1,
+                        Some(b'u') => break,
+                        Some(_) => continue 'outer,
+                    }
+                }
+
+                length += 1;
+
+                // u.
+
+                loop {
+                    match iter.next() {
+                        None => {
+                            result = result.max(length);
+
+                            break 'outer;
+                        }
+                        Some(b'a') => {
+                            result = result.max(length);
+
+                            continue 'start;
+                        }
+                        Some(b'u') => length += 1,
+                        Some(_) => {
+                            result = result.max(length);
+
+                            continue 'outer;
+                        }
+                    }
+                }
+            }
+        }
+
+        result
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn longest_beautiful_substring(word: String) -> i32 {
+        Self::longest_beautiful_substring(word)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}