290. Word Pattern

最新推荐文章于 2024-03-05 15:25:25 发布

原创最新推荐文章于 2024-03-05 15:25:25 发布 · 260 阅读

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本文探讨了如何使用Map数据结构解决字符串模式匹配问题，详细解释了算法逻辑和实现细节，包括实例分析。

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:
pattern = "abba", str = "dog cat cat dog" should return true.
pattern = "abba", str = "dog cat cat fish" should return false.
pattern = "aaaa", str = "dog cat cat dog" should return false.
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.

看了别人实现的代码挺好的。用到的数据结构是Map.

public static  boolean wordPattern(String pattern, String str) {

        char[] patternList = pattern.toCharArray();
        String[] strList = str.split(" ");

        if (pattern.length() != strList.length) 
            return false;
        Map<String, String> map = new HashMap<>();
        for (int i = 0; i < patternList.length; i++) {
           String c  = patternList[i]+"";

           //判断是否已经存在了。如果存在判断value是否相等。
           if(map.containsKey(c))
           {
               if(!map.get(c).equals(strList[i]))
                   return false;
           }
           //key不存在，但是value存在，意味着匹配已经出现了失误。
           else if(map.containsValue(strList[i]))
           {
               return false;
           }else
           {
               map.put(c, strList[i]);
           }
        }
        //在
        return true;
    }