290 - Word Pattern.

Easy

Given a pattern and a string s, find if s 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 s.

Example 1:

Input: pattern = "abba", s = "dog cat cat dog"

Output: true

Example 2:

Input: pattern = "abba", s = "dog cat cat fish"

Output: false

Example 3:

Input: pattern = "aaaa", s = "dog cat cat dog"

Output: false

Constraints:

• 1 <= pattern.length <= 300

• pattern contains only lower-case English letters.

• 1 <= s.length <= 3000

• s contains only lowercase English letters and spaces ' '.

• s does not contain any leading or trailing spaces.

• All the words in s are separated by a single space.