问C++/JAVA:高效地在集合中找到包含给定值的集合

EN

int getSetIndex(Object elem) {
    Set first = sets.get(0);
    if (first.contains(elem))
        // if "index of the set" has some special meaning in your question,
        // you should save it along with the set
        return first.index();
    for (int i = 1; i < sets.size(); i++) {
        Set cur = sets.get(i);
        if (cur.contains(elem)) {
            sets.set(i, sets.get(i - 1));
            sets.set(i - 1, cur);
            return cur.index();
        }
    }
    return -1; // not found
}