/**
* Helper function for contains that takes in a String s and a LetterNode letter and verifies that
* the first letter of s matches the LetterNode letter. If this does not hold; returns false.
*
* @param s is the prefix being checked if it is in the dictionary
* @param letter is compared to the first letter of s to see if s is in the dictionary
*/
public boolean containsHelper(String s, LetterNode w) {
// If w's letter is equal to the first letter of s
if (w.toString().equals(s.substring(0, 1))) {
// If s has one letter and the corresponding TreeNode
// completesFullWord, then the word is in the Trie.
if (s.length() == 1) {
if (w.completesFullWord) {
return true;
} else {
return false;
}
} else {
LetterNode nextPossible = w.getNextLetter(s.substring(1, 2));
// If child LetterNode corresponding to the next letter does not exist
if (nextPossible == null) {
return false;
} else {
return containsHelper(s.substring(1), nextPossible);
}
}
}
return false;
}
/**
* Helper function for containsPrefix that takes in a String s and a LetterNode letter and
* verifies that the first letter of s matches the LetterNode letter. If this does not hold;
* returns false.
*
* @param s is the prefix being checked if it is in the dictionary
* @param letter is compared to the first letter of s to see if s is in the dictionary
*/
private boolean containsPrefixHelper(String s, LetterNode letter) {
// If w's letter is equal to the first letter of s
if (letter.toString().equals(s.substring(0, 1))) {
// If s has one letter, then the prefix is in the Trie.
if (s.length() == 1) {
return true;
} else {
LetterNode nextPossible = letter.getNextLetter(s.substring(1, 2));
// If child LetterNode corresponding to the next letter does not exist
if (nextPossible == null) {
return false;
} else {
return containsPrefixHelper(s.substring(1), nextPossible);
}
}
}
return false;
}