001
002
003
004
005
006
007
008
009
010
011
012
013
014
015
016
017
018
019
020
021
022
023
024
025
026
027
028
029
030
031
032
033
034
035
036
037
038
039
040
041
042
043
044
045
046
047
048
049
050
051
052
053
054
055
056
057
058
059
060
061
062
063
064
065
066
067
068
069
070
071
072
073
074
075
076
077
078
079
080
081
082
083
084
085
086
087
088
089
090
091
092
093
094
095
096
097
098
099
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
package algs52; // section 5.2
import stdlib.*;
import algs13.Queue;
/* ***********************************************************************
 *  Compilation:  javac TST.java
 *  Execution:    java TST < words.txt
 *  Dependencies: StdIn.java
 *
 *  Symbol table with string keys, implemented using a ternary search
 *  trie (TST).
 *
 *
 *  % java TST < shellsST.txt
 *  by 4
 *  sea 6
 *  sells 1
 *  she 0
 *  shells 3
 *  shore 7
 *  the 5

 *
 *  % java TST
 *  theory the now is the time for all good men

 *  Remarks
 *  --------
 *    - can't use a key that is the empty string ""
 *
 *************************************************************************/

public class TST<V> {
  private int N;       // size
  private Node<V> root;   // root of TST

  private static class Node<V> {
    public Node() { }
    public char c;                 // character
    public Node<V> left, mid, right;  // left, middle, and right subtries
    public V val;              // value associated with string
  }

  // return number of key-value pairs
  public int size() {
    return N;
  }

  /* ************************************************************
   * Is string key in the symbol table?
   **************************************************************/
  public boolean contains(String key) {
    return get(key) != null;
  }

  public V get(String key) {
    if (key == null || key.length() == 0) throw new Error("illegal key");
    Node<V> x = get(root, key, 0);
    if (x == null) return null;
    return x.val;
  }

  // return subtrie corresponding to given key
  private Node<V> get(Node<V> x, String key, int d) {
    if (key == null || key.length() == 0) throw new Error("illegal key");
    if (x == null) return null;
    char c = key.charAt(d);
    if      (c < x.c)              return get(x.left,  key, d);
    else if (c > x.c)              return get(x.right, key, d);
    else if (d < key.length() - 1) return get(x.mid,   key, d+1);
    else                           return x;
  }


  /* ************************************************************
   * Insert string s into the symbol table.
   **************************************************************/
  public void put(String s, V val) {
    if (!contains(s)) N++;
    root = put(root, s, val, 0);
  }

  private Node<V> put(Node<V> x, String s, V val, int d) {
    char c = s.charAt(d);
    if (x == null) {
      x = new Node<>();
      x.c = c;
    }
    if      (c < x.c)             x.left  = put(x.left,  s, val, d);
    else if (c > x.c)             x.right = put(x.right, s, val, d);
    else if (d < s.length() - 1)  x.mid   = put(x.mid,   s, val, d+1);
    else                          x.val   = val;
    return x;
  }


  /* ************************************************************
   * Find and return longest prefix of s in TST
   **************************************************************/
  public String longestPrefixOf(String s) {
    if (s == null || s.length() == 0) return null;
    int length = 0;
    Node<V> x = root;
    int i = 0;
    while (x != null && i < s.length()) {
      char c = s.charAt(i);
      if      (c < x.c) x = x.left;
      else if (c > x.c) x = x.right;
      else {
        i++;
        if (x.val != null) length = i;
        x = x.mid;
      }
    }
    return s.substring(0, length);
  }

  // all keys in symbol table
  public Iterable<String> keys() {
    Queue<String> queue = new Queue<>();
    collect(root, "", queue);
    return queue;
  }

  // all keys starting with given prefix
  public Iterable<String> prefixMatch(String prefix) {
    Queue<String> queue = new Queue<>();
    Node<V> x = get(root, prefix, 0);
    if (x == null) return queue;
    if (x.val != null) queue.enqueue(prefix);
    collect(x.mid, prefix, queue);
    return queue;
  }

  // all keys in subtrie rooted at x with given prefix
  private void collect(Node<V> x, String prefix, Queue<String> queue) {
    if (x == null) return;
    collect(x.left,  prefix,       queue);
    if (x.val != null) queue.enqueue(prefix + x.c);
    collect(x.mid,   prefix + x.c, queue);
    collect(x.right, prefix,       queue);
  }


  // return all keys matching given wilcard pattern
  public Iterable<String> wildcardMatch(String pat) {
    Queue<String> queue = new Queue<>();
    collect(root, "", 0, pat, queue);
    return queue;
  }

  private void collect(Node<V> x, String prefix, int i, String pat, Queue<String> q) {
    if (x == null) return;
    char c = pat.charAt(i);
    if (c == '.' || c < x.c) collect(x.left, prefix, i, pat, q);
    if (c == '.' || c == x.c) {
      if (i == pat.length() - 1 && x.val != null) q.enqueue(prefix + x.c);
      if (i < pat.length() - 1) collect(x.mid, prefix + x.c, i+1, pat, q);
    }
    if (c == '.' || c > x.c) collect(x.right, prefix, i, pat, q);
  }



  // test client
  public static void main(String[] args) {
    // build symbol table from standard input
    TST<Integer> st = new TST<>();
    for (int i = 0; !StdIn.isEmpty(); i++) {
      String key = StdIn.readString();
      st.put(key, i);
    }


    // print results
    for (String key : st.keys()) {
      StdOut.println(key + " " + st.get(key));
    }
  }
}