java - Get Words out of a Trie Data Structure -

i have following trie data structure:

public class cdictionary implements idictionary {  private static final int n = 'z' -'a'+1;  private static class node {     private boolean end = false;     private node[] next = new node[n]; }  private int size = 0; private node root = new node();  @override public boolean contains(string word) {     node node = this.contains(root,word,0);     if (node == null) {         return false;     }     return node.end; }  private node contains(node node, string str, int d) {     if (node == null) return null;     if (d == str.length()) return node;      char c = str.charat(d);     return contains(node.next[c-'a'], str, d+1); }  @override public void insert(string word) {     this.root = insert(this.root, word, 0);     this.size++; }  private node insert(node node, string str, int d) {     if (node == null) node = new node();     if (d == str.length()) {         node.end = true;         return node;     }      char c = str.charat(d);     node.next[c-'a'] = this.insert(node.next[c-'a'], str, d+1);     return node; }  @override public int size() {     return size; } 

the trie filled words like

for, the, each, home, is, it, egg, red...

now need function words specific length example length 3

public list<string> getwords(int lenght) {  } 

with words mentioned above should return list words

for,the,egg,red

the problem how can restore these words out of trie structur?

you need recurse through structure maximum depth of n (in case 3)

you adding couple of methods dictionary...

public list<string> findwordsoflength(int length) {     // create new empty list results     list<string> results = new arraylist<>();     // start @ root node (level 0)...     findwordsoflength(root, "", 0, length, results);     // return results     return results; }  public void findwordsoflength(node node, string wordsofar, int depth, int maxdepth, list<string> results) {     // go through each "child" of node     for(int k = 0; k < node.next.length; k++) {        node child = node.next[k];        // if child exists...        if(child != null) {            // work out letter child represents            char letter = 'a' + k;            // if have reached "maxdepth" letters...            if(depth == maxdepth) {                // add letter end of word far , add word results list                results.add(wordsofar + letter);            } else {                // otherwise recurse next level                findwordsoflength(child, wordsodar + letter, depth + 1, maxdepth, results);            }        }     } } 

(i have not compiled / tested this, should give idea of need do)

hope helps.