FRQ list analysis

FRQ Question 3 (Data Analysis with ArrayList) provides a class and asks you to write one method. The recurring algorithm shapes:

Filter into a new list (no mutation of the source):

public static ArrayList<String> longWords(ArrayList<String> words) {
    ArrayList<String> out = new ArrayList<String>();
    for (String w : words) {
        if (w.length() >= 5) {
            out.add(w);
        }
    }
    return out;
}

Aggregate:

public static int totalLetters(ArrayList<String> words) {
    int total = 0;
    for (String w : words) {
        total += w.length();
    }
    return total;
}

Conditional removal — the backwards walk:

public static void removeShort(ArrayList<String> words) {
    for (int i = words.size() - 1; i >= 0; i--) {
        if (words.get(i).length() < 3) {
            words.remove(i);
        }
    }
}

Find max/count by property mixes M9's patterns with .get(i) syntax. One more spec-reading note: FRQ specs say things like "the list contains at least one element" — that is your license to seed best = list.get(0) without an empty-list branch.