// optimized for search - O(1) for searching for a token // set is O(m) with m = number of occurrences of token // This could be improved to O(log m) by using a TreeSet instead of the L in the index final sclass TokenIndexedList3 extends RandomAccessAbstractList { new Map> index; // tokens by contents, sorted by index new L list; sclass Token implements Comparable { int i; // index in list S s; // actual token public int compareTo(Token t) { ret i-t.i; } } *() {} *(Collection l) { addAll(l); } public S get(int i) { ret list.get(i).s; } public int size() { ret list.size(); } public S set(int i, S s) { Token t = list.get(i); S old = t.s; if (eq(old, s)) ret old; removeFromIdx(t); t.s = s; addToIdx(t); ret old; } public bool add(S s) { ++modCount; new Token t; t.s = s; t.i = size(); list.add(t); addToIdx(t); true; } public void add(int i, S s) { ++modCount; new Token t; t.s = s; t.i = i; list.add(i, t); reorder(i+1); addToIdx(t); } public bool addAll(int i, Collection l) { int n = l.size(); if (n == 0) false; ++modCount; L l2 = emptyList(n); int j = i; for (S s : l) { new Token t; t.s = s; t.i = j++; l2.add(t); } list.addAll(i, l2); reorder(i+n); for (Token t : l2) addToIdx(t); true; } public S remove(int i) { ++modCount; Token t = list.get(i); removeFromIdx(t); list.remove(i); reorder(i); ret t.s; } void reorder(int fromIdx) { int n = size(); for (int i = fromIdx; i < n; i++) list.get(i).i = i; } void removeFromIdx(Token t) { TreeSet idx = index.get(t.s); idx.remove(t); if (idx.isEmpty()) index.remove(t.s); } void addToIdx(Token t) { TreeSet idx = index.get(t.s); if (idx == null) index.put(t.s, idx = new TreeSet); idx.add(t); } Comparator comparator() { ret (Comparator) (a, b) -> b.i-a.i; } public int indexOf(S s) { TreeSet l = index.get(s); ret l == null ? -1 : first(l).i; } public bool contains(O s) { ret index.containsKey(s); } public void clear() { ++modCount; index.clear(); list.clear(); } protected void removeRange(int fromIndex, int toIndex) { if (fromIndex == toIndex) ret; ++modCount; // TODO: this can be optimized for (int i = fromIndex; i < toIndex; i++) removeFromIdx(list.get(i)); list.subList(fromIndex, toIndex).clear(); reorder(fromIndex); } }