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CanArrangeWords.java
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31 lines (27 loc) · 933 Bytes
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import java.util.HashSet;
/**
* 单词接龙，前一个单词的尾巴和后一个单词的头相同就算接上了
* 如果要返回接龙的结果，可以给HashSet改成List
* 如果要返回所有可能的结果呢？
*/
public class CanArrangeWords {
public static boolean canArrangeWords(String[] words) {
HashSet<String> set = new HashSet<String>();
return helper(null, words, set);
}
public static boolean helper(String word, String[] words, HashSet<String> set) {
if (set.size() == words.length) {
return true;
}
for (String s : words) {
if (!set.contains(s) && (word == null || s.charAt(0) == word.charAt(word.length() - 1))) {
set.add(s);
if (helper(s, words, set)) {
return true;
}
set.remove(s);
}
}
return false;
}
}