binary search tree java

import java.util.ArrayList; import java.util.List; public class FrequencyFilter { // You should use the string constants below for throwing exceptions: // e.g. throw new IllegalArgumentException(ILLEGAL_ARG_BAD_RANGE); public static final String ILLEGAL_ARG_LENGTH = "List must be same length as number of trees"; public static final String ILLEGAL_ARG_BAD_RANGE = "maxPrefixLen cannot be less than minPrefixLen"; public static final String ILLEGAL_ARG_MIN_PREFIX = "maxPrefixLen must be positive"; // Array of BSTs that map prefixes to frequency (number of occurrences) private BST<String, Integer>[] frequencyTrees; /** * Builds this FrequencyFilter's frequencyTrees array of BSTs. * Each element in the array is a BST whose keys are the prefixes of a certain length * and values are the frequency of each prefix * @param data the data from which to parse prefixes * @param minPrefixLen the minimum prefix length, inclusive, equivalent to the prefix length of * the first BST in the this FrequencyFilter's frequencyTrees array * @param maxPrefixLen the maximum prefix length, inclusive, equivalent to the prefix length of * the last BST in the this FrequencyFilter's frequencyTrees array * * @throws IllegalArgumentException if maxPrefixLen is less than minPrefixLen or minPrefixLen not positive */ public void buildFrequencyTrees(String data, int minPrefixLen, int maxPrefixLen) throws IllegalArgumentException { // TODO } /** * Filters every BST in this FrequencyFilter's frequencyTrees array, removing any elements * whose frequency falls below the cutoff frequency. That is, if a prefix occurs less than the * cutoff frequency, it is removed * @param freq the cutoff frequency * @return a modified String representation of each tree in this FrequencyFilter, as specified * in the PA7 spec. */ public List<String> filter(int freq) { // TODO return new ArrayList<>(); } /** * Filters every BST as in filter(int freq) above, except that each BST is filtered with its * own cutoff frequency. * @param freqs the cutoff frequencies to filter the BSTs with. Each element in freqs is * applied to one corresponding BST (same index). * @return a modified String representation of each tree in this FrequencyFilter, as specified * in the PA7 spec. * @throws IllegalArgumentException if the length of freqs and frequencyTrees is not the same */ public List<String> filter(int[] freqs) throws IllegalArgumentException { // TODO return new ArrayList<>(); } }