isInOrder.java

public static boolean isInOrder(String input, String ordering) {

        class PairChar {
            int first = Integer.MAX_VALUE;
            int last = -1;
        }

        char[] orderArr = ordering.toCharArray();
        char[] inputArr = input.toCharArray();
        HashMap<Character, PairChar> map = new HashMap<>();

        for (int i = 0; i < inputArr.length; i++) {
            PairChar pair = map.get(inputArr[i]);
            if (pair == null) {
                pair = new PairChar();
                pair.first = i;
                pair.last = i;
                map.put(inputArr[i], pair);
            } else {
                pair.last = i;
                map.put(inputArr[i], pair);
            }

        }
        PairChar prevPair = new PairChar();
        PairChar currentPair;
        for (char ordrChr : orderArr) {
            if (map.get(ordrChr)== null) {
                return false; //case when input has NO elements of order string
            }
            currentPair= map.get(ordrChr);
            if (prevPair.last > currentPair.first) {
                return false;
            } else {
                prevPair = currentPair;
            }
        }
        return true;
    }