字典树Java模板

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package binarytree;  /**  * 字典树的Java实现。实现了插入、查询以及深度优先遍历.  * Trie tree's java implementation.(Insert,Search,DFS)  * @author jiutianhe  * @time 2012.10.16  */  public class TrieTree {      final int MAX_SIZE=26;      public class TrieTreeNode {               int nCount;//记录该字符出现次数          char ch; //记录该字符          TrieTreeNode[] child;          public TrieTreeNode() {              nCount=1;              child=new TrieTreeNode[MAX_SIZE];          }      }      //字典树的插入和构建      public void createTrie(TrieTreeNode node,String str){          if (str==null||str.length()==0) {              return;          }          char[] letters=str.toCharArray();          for (int i = 0; i < letters.length; i++) {              int pos = letters[i] - 'a';                if (node.child[pos] == null) {                    node.child[pos] = new TrieTreeNode();                 }else {                  node.child[pos].nCount++;              }              node.ch=letters[i];                          node = node.child[pos];                      }      }      //字典树的查找      public int findCount(TrieTreeNode node,String str){          if (str==null||str.length()==0) {              return -1;          }          char[] letters=str.toCharArray();          for (int i = 0; i < letters.length; i++) {              int pos = letters[i] - 'a';                if (node.child[pos] == null) {                    return 0;                 }else {                  node=node.child[pos];              }                     }          return node.nCount;      }  }  [java] view plain copy 在CODE上查看代码片派生到我的代码片@Test      public void trieTreeTest2(){      /**      * Problem Description        * 老师交给他很多单词(只有小写字母组成,不会有重复的单词出现),现在老师要他统计      * 出以某个字符串为前缀的单词数量(单词本身也是自己的前缀).        */          String[] strs={                     "banana",                     "band",                     "bee",                     "absolute",                     "acm",             };             String[] prefix={                 "ba",                 "b",                 "band",                 "abc",             };            TrieTree tree = new TrieTree();          TrieTreeNode root=tree.new TrieTreeNode();          for (String s : strs) {                tree.createTrie(root, s);            }     //        tree.printAllWords();             for(String pre:prefix){                 int num=tree.findCount(root,pre);                 System.out.println(pre+" "+num);             }      }
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