程序包 edu.princeton.cs.algs4

类 TST<Value>

  • public class TST<Value>
extends java.lang.Object
    The TST class represents an symbol table of key-value pairs, with string keys and generic values. It supports the usual put, get, contains, delete, size, and is-empty methods. It also provides character-based methods for finding the string in the symbol table that is the longest prefix of a given prefix, finding all strings in the symbol table that start with a given prefix, and finding all strings in the symbol table that match a given pattern. A symbol table implements the associative array abstraction: when associating a value with a key that is already in the symbol table, the convention is to replace the old value with the new value. Unlike Map, this class uses the convention that values cannot be null—setting the value associated with a key to null is equivalent to deleting the key from the symbol table.

    This implementation uses a ternary search trie.

    For additional documentation, see Section 5.2 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

    • 构造器概要

      构造器 
      构造器 说明
      TST()
      Initializes an empty string symbol table.

    • 方法概要

      修饰符和类型 方法 说明
      boolean contains​(java.lang.String key)
      Does this symbol table contain the given key?
      Value get​(java.lang.String key)
      Returns the value associated with the given key.
      java.lang.Iterable<java.lang.String> keys()
      Returns all keys in the symbol table as an Iterable.
      java.lang.Iterable<java.lang.String> keysThatMatch​(java.lang.String pattern)
      Returns all of the keys in the symbol table that match pattern, where . symbol is treated as a wildcard character.
      java.lang.Iterable<java.lang.String> keysWithPrefix​(java.lang.String prefix)
      Returns all of the keys in the set that start with prefix.
      java.lang.String longestPrefixOf​(java.lang.String query)
      Returns the string in the symbol table that is the longest prefix of query, or null, if no such string.
      static void main​(java.lang.String[] args)
      Unit tests the TST data type.
      void put​(java.lang.String key, Value val)
      Inserts the key-value pair into the symbol table, overwriting the old value with the new value if the key is already in the symbol table.
      int size()
      Returns the number of key-value pairs in this symbol table.

      • 从类继承的方法 java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • 构造器详细资料

      • TST

        public TST()
        Initializes an empty string symbol table.

    • 方法详细资料

      • size

        public int size()
        Returns the number of key-value pairs in this symbol table.
        返回:
        the number of key-value pairs in this symbol table

      • contains

        public boolean contains​(java.lang.String key)
        Does this symbol table contain the given key?
        参数:
        key - the key
        返回:
        true if this symbol table contains key and false otherwise
        抛出:
        java.lang.IllegalArgumentException - if key is null

      • get

        public Value get​(java.lang.String key)
        Returns the value associated with the given key.
        参数:
        key - the key
        返回:
        the value associated with the given key if the key is in the symbol table and null if the key is not in the symbol table
        抛出:
        java.lang.IllegalArgumentException - if key is null

      • put

        public void put​(java.lang.String key,
                Value val)
        Inserts the key-value pair into the symbol table, overwriting the old value with the new value if the key is already in the symbol table. If the value is null, this effectively deletes the key from the symbol table.
        参数:
        key - the key
        val - the value
        抛出:
        java.lang.IllegalArgumentException - if key is null

      • longestPrefixOf

        public java.lang.String longestPrefixOf​(java.lang.String query)
        Returns the string in the symbol table that is the longest prefix of query, or null, if no such string.
        参数:
        query - the query string
        返回:
        the string in the symbol table that is the longest prefix of query, or null if no such string
        抛出:
        java.lang.IllegalArgumentException - if query is null

      • keys

        public java.lang.Iterable<java.lang.String> keys()
        Returns all keys in the symbol table as an Iterable. To iterate over all of the keys in the symbol table named st, use the foreach notation: for (Key key : st.keys()).
        返回:
        all keys in the symbol table as an Iterable

      • keysWithPrefix

        public java.lang.Iterable<java.lang.String> keysWithPrefix​(java.lang.String prefix)
        Returns all of the keys in the set that start with prefix.
        参数:
        prefix - the prefix
        返回:
        all of the keys in the set that start with prefix, as an iterable
        抛出:
        java.lang.IllegalArgumentException - if prefix is null

      • keysThatMatch

        public java.lang.Iterable<java.lang.String> keysThatMatch​(java.lang.String pattern)
        Returns all of the keys in the symbol table that match pattern, where . symbol is treated as a wildcard character.
        参数:
        pattern - the pattern
        返回:
        all of the keys in the symbol table that match pattern, as an iterable, where . is treated as a wildcard character.

      • main

        public static void main​(java.lang.String[] args)
        Unit tests the TST data type.
        参数:
        args - the command-line arguments