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.

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

题目含义：给定一个模式，判断句子中的单词是否满足模式？

 

    public boolean wordPattern(String pattern, String str) {
        if(str.split(" ").length != pattern.length()) return false;
        Map<Character,String> map = new HashMap<>(pattern.length());//维护pattern字符与后面字符串的映射关系
        Map<String,Boolean> valueMap = new HashMap<>();
        
        char p_arra[] = pattern.toCharArray();
        String str_arra[] = str.split(" ");
        int index=0;
        while (index<p_arra.length)
        {
            if (!map.containsKey(p_arra[index]))
            {
                if (valueMap.containsKey(str_arra[index])) return false;
                map.put(p_arra[index],str_arra[index]);
                valueMap.put(str_arra[index],true);
            }else if (!map.get(p_arra[index]).equals(str_arra[index])) return false;
            index++;
        }
        return true;        
    }