public static String reverseWords(String input){

String[] arr = input.trim().split("\\s+");//"\\s+"

int len = arr.length;

/*

String[] result = new String[len];

for (int i = 0;i<len;i++){

result[len-1-i] = arr[i];

}

return Arrays.toString(result);//[blue, is, sky, the]

*/

StringBuilder sb = new StringBuilder();

for (int i = 0;i<len;i++){

sb.append(arr[len-1-i]);

if (len == 1){

}else if(i<len-1)

sb.append(" ");

}

return sb.toString();

}

public static int compress(char[] chars) {

Map<Character, String> map = new LinkedHashMap();

int len = chars.length;

for (int i = 0; i<len;i++){

if (map.containsKey(chars[i])){

map.put(chars[i],String.valueOf(Integer.parseInt(map.get(chars[i])) + 1));

}else map.put(chars[i],"1");

}

int num = 0;

for (Map.Entry<Character, String> entry : map.entrySet()) {

num++;

if (!entry.getValue().equals("1")){

num += entry.getValue().toCharArray().length ;

}

}

return num;

}