Answer:
/ Main.java
class Main {
public static void main(String[] args) {
//System.out.println(inDogish("aplderogad"));
//System.out.println(inXish("aplderogad", "dog"));
}
// returns true if the word is in dog-ish
// returns false if word is not in dog-ish
public static boolean inDogish(String word) {
/**
* Note: we can use the inXish() method to complete this method in a
* single line if you want. just write 'return inXish(word,"dog");' and
* you are done.
*/
// if word is null or empty, returning false
if (word == null || word.length() == 0) {
return false;
}
// converting word to lower case
word = word.toLowerCase();
// if 'd' does not exist on the word, returning false
if (!dogishHelper(word, 'd')) {
return false;
}
// removing the characters upto first 'd' in word
word = word.substring(word.indexOf('d') + 1);
// if 'o' does not exist on the word, returning false
if (!dogishHelper(word, 'o')) {
return false;
}
// removing the characters upto first 'o' in word
word = word.substring(word.indexOf('o') + 1);
// if 'g' does not exist on the word, returning false, otherwise
// returning true
if (!dogishHelper(word, 'g')) {
return false;
} else {
return true;
}
}
// necessary to implement inDogish recursively.
// returns true if letter is in word, else not.
public static boolean dogishHelper(String word, char letter) {
// if word is empty, returning -1
if (word == null || word.length() == 0) {
return false;
}
// if first character in word is letter, returning 0
if (word.charAt(0) == letter) {
return true;
}
return dogishHelper(word.substring(1), letter);
}
// the best thing about the above helper method is that we can use it in
// inXish method also
// a generalized version of the inDogish method
public static boolean inXish(String word, String x) {
// if x is empty, returning true (base case, which means all the letters
// in x are in word in that order)
if (x.length() == 0) {
return true;
}
// getting first character of x
char first = x.charAt(0);
// if first character does not exist on the word, returning false
if (!dogishHelper(word, first)) {
return false;
}
// calling and returning inXish recursively, passing the word after
// removing characters upto first occurrance of char first, and x after
// removing first character from it
return inXish(word.substring(word.indexOf(first) + 1), x.substring(1));
}
}
Explanation: