import java.util.HashSet;
import java.util.Set;
import java.util.Stack;
import java.util.StringTokenizer;
/**
*
* @author athakur
*
*/
public class RemoveDuplicates {
public static void main(String args[]) {
String input = "Beginning with the first first first first manned Gemini mission in March 1965, commemorative commemorative medallions were prepared for the astronauts at their request. It is unclear who prepared these early medallions only only, only that each individual box containing a medallion bore the word Fliteline.";
System.out.println(removeConsecutiveDuplicates(input));
System.out.println(removeConsecutiveDuplicatesBetter(input));
System.out.println(removeAllDuplicates(input));
}
public static String removeAllDuplicates(String input) {
StringBuilder outputBuilder = new StringBuilder();
Set<String> wordsSet = new HashSet<>();
StringTokenizer tokenizer = new StringTokenizer(input, " ");
while (tokenizer.hasMoreTokens()) {
String word = tokenizer.nextToken();
if (wordsSet.add(word)) {
outputBuilder.append(word);
outputBuilder.append(" ");
}
}
return outputBuilder.toString();
}
public static String removeConsecutiveDuplicatesBetter(String input) {
StringBuilder outputBuilder = new StringBuilder();
String lastWord = "";
StringTokenizer tokenizer = new StringTokenizer(input, " ");
while (tokenizer.hasMoreTokens()) {
String word = tokenizer.nextToken();
if (!word.equalsIgnoreCase(lastWord)) {
outputBuilder.append(word);
outputBuilder.append(" ");
}
lastWord = word;
}
return outputBuilder.toString();
}
public static String removeConsecutiveDuplicates(String input) {
if (input == null)
return null;
Stack<String> wordsStack = new Stack<>();
String[] words = input.split(" ");
for (int i = 0; i < words.length; i++) {
wordsStack.push(words[i]);
}
String lastWord = "";
String stringWithNoConsecutiveDuplicates = "";
while (!wordsStack.isEmpty()) {
String tempPop = wordsStack.pop();
if (!lastWord.equalsIgnoreCase(tempPop)) {
stringWithNoConsecutiveDuplicates = tempPop + " "
+ stringWithNoConsecutiveDuplicates;
}
lastWord = tempPop;
}
return stringWithNoConsecutiveDuplicates;
}
}
