From 184e456e1b3090d9b26bafef2cd151d49e898672 Mon Sep 17 00:00:00 2001
From: Bauke <me@bauke.xyz>
Date: Sun, 10 Apr 2022 22:41:34 +0200
Subject: [PATCH] Solve word-pattern.

---
 source/lib.rs              |  1 +
 source/word_pattern/mod.rs | 22 ++++++++++++++++++++++
 tests/word_pattern.rs      | 16 ++++++++++++++++
 3 files changed, 39 insertions(+)
 create mode 100644 source/word_pattern/mod.rs
 create mode 100644 tests/word_pattern.rs

diff --git a/source/lib.rs b/source/lib.rs
index f1b2545..efcc123 100644
--- a/source/lib.rs
+++ b/source/lib.rs
@@ -15,3 +15,4 @@ pub mod two_sum;
 pub mod valid_anagram;
 pub mod valid_palindrome;
 pub mod valid_parenthesis;
+pub mod word_pattern;
diff --git a/source/word_pattern/mod.rs b/source/word_pattern/mod.rs
new file mode 100644
index 0000000..1ce3d5b
--- /dev/null
+++ b/source/word_pattern/mod.rs
@@ -0,0 +1,22 @@
+pub fn word_pattern(pattern: String, string: String) -> bool {
+  let mut key_map = std::collections::HashMap::new();
+  let mut value_map = std::collections::HashMap::new();
+
+  let mut pattern_iter = pattern.chars();
+  let mut string_iter = string.split_whitespace();
+
+  if pattern.len() != string_iter.clone().collect::<Vec<_>>().len() {
+    return false;
+  }
+
+  for (key, value) in pattern_iter.by_ref().zip(string_iter.by_ref()) {
+    let expected_value = *key_map.entry(key).or_insert(value);
+    let expected_key = *value_map.entry(value).or_insert(key);
+
+    if expected_key != key || expected_value != value {
+      return false;
+    }
+  }
+
+  pattern_iter.next().is_none() && string_iter.next().is_none()
+}
diff --git a/tests/word_pattern.rs b/tests/word_pattern.rs
new file mode 100644
index 0000000..d49bd51
--- /dev/null
+++ b/tests/word_pattern.rs
@@ -0,0 +1,16 @@
+use leetcode::word_pattern::word_pattern;
+
+use test_case::test_case;
+
+#[test_case("abba", "dog cat cat dog", true; "example 1")]
+#[test_case("abba", "dog cat cat fish", false; "example 2")]
+#[test_case("aaaa", "dog cat cat dog", false; "example 3")]
+#[test_case("abba", "dog dog dog dog", false; "unique key value pair")]
+#[test_case("aaa", "aa aa aa aa", false; "longer string")]
+#[test_case("he", "unit", false; "longer pattern")]
+fn test_word_pattern(pattern: &str, string: &str, expected: bool) {
+  assert_eq!(
+    word_pattern(pattern.to_string(), string.to_string()),
+    expected
+  );
+}