Solve #290

Author: aylei

src/lib.rs

@@ -219,3 +219,4 @@ mod n0282_expression_add_operators;
 mod n0283_move_zeroes;
 mod n0287_find_the_duplicate_number;
 mod n0289_game_of_life;
+mod n0290_word_pattern;

src/n0290_word_pattern.rs

@@ -0,0 +1,75 @@
+/**
+ * [290] Word Pattern
+ *
+ * Given a pattern and a string str, find if str follows the same pattern.
+ *
+ * Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.
+ *
+ * Example 1:
+ *
+ *
+ * Input: pattern = "abba", str = "dog cat cat dog"
+ * Output: true
+ *
+ * Example 2:
+ *
+ *
+ * Input:pattern = "abba", str = "dog cat cat fish"
+ * Output: false
+ *
+ * Example 3:
+ *
+ *
+ * Input: pattern = "aaaa", str = "dog cat cat dog"
+ * Output: false
+ *
+ * Example 4:
+ *
+ *
+ * Input: pattern = "abba", str = "dog dog dog dog"
+ * Output: false
+ *
+ * Notes:<br />
+ * You may assume pattern contains only lowercase letters, and str contains lowercase letters that may be separated by a single space.
+ *
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+use std::collections::HashMap;
+impl Solution {
+    pub fn word_pattern(pattern: String, s: String) -> bool {
+        let mut p2s = HashMap::new();
+        let mut s2p = HashMap::new();
+        let mut s_iter = s.split(" ");
+        let mut p_iter = pattern.chars();
+        loop {
+            match (s_iter.next(), p_iter.next()) {
+                (Some(sub), Some(ch)) => {
+                    if *p2s.entry(ch).or_insert(sub) != sub ||
+                        *s2p.entry(sub).or_insert(ch) != ch {
+                        return false
+                    }
+                },
+                (None, None) => break,
+                _ => return false,
+            }
+        }
+        true
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_290() {
+        assert_eq!(Solution::word_pattern("abba".to_owned(), "dog cat cat dog".to_owned()), true);
+        assert_eq!(Solution::word_pattern("aaaa".to_owned(), "dog cat cat dog".to_owned()), false);
+        assert_eq!(Solution::word_pattern("abba".to_owned(), "dog cat cat fish".to_owned()), false);
+    }
+}