[LeetCode 290] Word Pattern

Given a pattern and a string str, find if str follows the same pattern.

Examples:

1. pattern = "abba", str = "dog cat cat dog" should return true.
2. pattern = "abba", str = "dog cat cat fish" should return false.
3. pattern = "aaaa", str = "dog cat cat dog" should return false.
4. pattern = "abba", str = "dog dog dog dog" should return false.

Notes:

1. patterncontains only lowercase alphabetical letters, and str contains words separated by a single space. Each word in str contains only lowercase alphabetical letters.
2. Both pattern and str do not have leading or trailing spaces.
3. Each letter in pattern must map to a word with length that is at least 1.

solution:

straight forward, use hashtable to store current map from pattern character to str string. If there exits and not match or string maps more than one letter return false.

public boolean wordPattern(String pattern, String str) {
        String[] strs = str.split(" ");
        if(pattern.length() != strs.length) return false;
        Map map = new HashMap();
        for(int i=0;i