LintCode 671 循环单词

最新推荐文章于 2019-01-29 23:27:32 发布

原创最新推荐文章于 2019-01-29 23:27:32 发布 · 854 阅读

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本文介绍了一种算法，用于计算给定字典中不同循环单词集的数量。通过将字符串旋转并加入到Set集合中来判断重复，实现了高效地统计。

The words are same rotate words if rotate the word to the right by loop, and get another. Count how many different rotate word sets in dictionary.

E.g. picture and turepic are same rotate words.

["picture", "turepic", "icturep", "word", "ordw", "lint"]
return 3.

“picture”, “turepic”, “icturep” are same ratote words.
“word”, “ordw” are same too.
“lint” is the third word that different from the previous two words.
将每个String的变化串加进Set集合中，进行重复判断。
解一：

//671循环单词
    public static int countRotateWords(List<String> words){
        int count=0;
        Set<String> set=new HashSet<String>();
            for (int i = 0; i < words.size(); i++) {
                String string=words.get(i);
                if (!set.contains(string)) {
                    count++;
                    set.add(string);
                    String b=change(string);
                    while(!b.equals(string)){
                        set.add(b);
                        b=change(b);
                    }
                }
            }


        return count;
    }

    public static String change(String string){
        String aString=string.substring(string.length()-1)
        +string.substring(0,string.length()-1);
        return aString;
    }