Solve word-pattern.

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;

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()
+}

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
+  );
+}