java-projects/anagrams/Anagrams.java

149 lines
4.6 KiB
Java

/**
*
* Matt Jensen
* 5/28/19
* CS 145
* Assignment 3 - Anagrams
*
* Finds and prints all anagrams for a specific phrase.
* Uses recursive backtracking.
*
*/
import java.util.*;
public class Anagrams {
private Set<String> dictionary;
private int max;
private String phrase;
private List<String> solution = new ArrayList<String>();
private Set<String[]> foundSolutions = new HashSet<String[]>();
private Map<String, LetterInventory> inventories = new HashMap<String, LetterInventory>();
public Anagrams(Set<String> dictionary){
this.setDictionary(dictionary);
}
// @returns words anagrams in dictionary made with the word
public Set<String> getWords(String phrase){
Set<String> anagrams = new TreeSet<String>();
if( ! this.inventories.keySet().contains(phrase) ) {
this.inventories.put(phrase, new LetterInventory(phrase));
}
LetterInventory inventory = this.getInventory(phrase);
for(String dictionaryWord : this.dictionary) {
if(inventory.contains(dictionaryWord)){
anagrams.add(dictionaryWord);
}
}
return anagrams;
}
// easier signature without max.
public void print(String phrase){
print(phrase, this.getWords(phrase).size());
}
// populates foundSolutions then prints each to console.
public void print(String phrase, int max){
this.setPhrase(phrase);
this.setMax(max);
this.findSolutions();
for(String[] solution : this.getSolutions() ) {
System.out.println(Arrays.toString(solution));
}
}
// private methods.
// called to populate foundSolutions.
private void findSolutions() {
this.foundSolutions = new HashSet<String[]>();
this.solution = new ArrayList<String>();
LetterInventory inventory = this.getInventory(this.getPhrase());
this.findSolutions(inventory);
}
private void findSolutions(LetterInventory remainingInventory) {
// check if solution
if(remainingInventory.isEmpty()) {
this.addSolution();
return;
}
// guesses.
Set<String> values = this.getWords(phrase);
for( String value : values ) {
if( isValid(value, remainingInventory) ) {
applyValue(value, remainingInventory);
findSolutions(remainingInventory);
removeValue(value, remainingInventory);
}
}
return;
}
// tests is the value makes the decision tree dead end.
private boolean isValid(String value, LetterInventory inventory) {
if( ! inventory.contains(value)) {
return false;
}
return true;
}
// backtracks the apply value step.
private void removeValue(String value, LetterInventory inventory) {
inventory.add(value);
this.solution.remove(value);
}
// adds the value to solution currently being built.
private void applyValue(String value, LetterInventory inventory) {
inventory.subtract(value);
this.solution.add(value);
}
// methods for saving a found solution
private void addSolution() {
if( this.solution.size() > this.max) {
return;
}
int i = 0;
String[] newSolution = new String[this.solution.size()];
for(String word : this.solution) {
newSolution[i] = word;
i++;
}
this.foundSolutions.add(newSolution);
}
// setters and getters for class variables.
private Set<String[]> getSolutions() {
return this.foundSolutions;
}
private List<String> getSolution() {
return this.solution;
}
private LetterInventory getInventory(String phrase) {
return this.inventories.get(phrase);
}
private void setDictionary(Set<String> dictionary) {
this.dictionary = dictionary;
}
// sets the max or as the total number of found words in the phrase.
private void setMax(int max) {
if( max > 0 ) {
this.max = max;
}
else{
this.max = this.getWords(this.getPhrase()).size();
}
}
// errors if phrase is null or sets class phrase variable.
private void setPhrase(String phrase) {
if(phrase == null) {
throw new IllegalArgumentException();
}
this.phrase = phrase;
}
private String getPhrase() {
return this.phrase;
}
}