LeetCode-Word-Pattern

---

title: LeetCode-Word-Pattern
date: 2019-01-31 12:23:25
tags: LeetCode
categories: LeetCode

290. Word Pattern

Difficulty: Easy

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:
You may assume pattern contains only lowercase letters, and str contains lowercase letters separated by a single space.

Solution

Language: Java

class Solution {

        public boolean wordPattern(String pattern, String str) {
        String[] words = str.split(" ");
        if (words.length != pattern.length())
            return false;
        Map<java.io.Serializable, Integer> index = new HashMap<java.io.Serializable, Integer>();
        for (Integer i = 0; i < words.length; ++i) {
            Integer left = index.put(pattern.charAt(i), i);
            Integer right = index.put(words[i], i);
            if (left != right) {
                return false;
            }
        }
        return true;
    }
}