java - Convert linked list in arrayList -

i want convert linkedlist arraylist

    date datainizio = new date();     linkedlist<node> queue = new linkedlist<node>();     int n = combinazioni.size();     arraylist<elemento> temp = new arraylist<elemento>();     temp.add(combinazioni.get(0));     queue.add(new node(0, temp));     // add different integers queue once.     (int = 1; < n; ++i) {         if (combinazioni.get(i - 1) == combinazioni.get(i)) {             continue;         }         temp = new arraylist<elemento>();         temp.add(combinazioni.get(i));         queue.add(new node(i, temp));     }     // bfs until have no elements     while (!queue.isempty()) {         node node = queue.remove();         if (node.lastindex + 1 < n) {             node newnode = new node(node);             newnode.lastindex = node.lastindex + 1;             newnode.currentlist.add(combinazioni.get(node.lastindex + 1));             queue.add(newnode);         }         (int = node.lastindex + 2; < n; ++i) {             if (combinazioni.get(i - 1) == combinazioni.get(i)) {                 continue;             }             // create copy , add integer             node newnode = new node(node);             newnode.lastindex = i;             newnode.currentlist.add(combinazioni.get(i));             queue.add(newnode);         }         gestoreregole gestoreregole = new gestoreregole();         gestoreregole.esegui(node.currentlist);     }     date dataf = new date();     long tempo = dataf.gettime() - datainizio.gettime();     logger.info("durata genera combinazioni: " + tempo); } 

most of collections in java have constructor takes compatible collection , generates copy of new type:

linkedlist<t> oldlist; arraylist<t> newlist = new arraylist<>(oldlist); 

which equivalent to:

linkedlist<t> oldlist; arraylist<t> newlist = new arraylist<>(); //optional: newlist.ensurecapacity(oldlist.size()); newlist.addall(oldlist); 

which equivalent to:

linkedlist<t> oldlist; arraylist<t> newlist = new arraylist<>(); //optional: newlist.ensurecapacity(oldlist.size()); (t element: oldlist) {   newlist.add(element); } 

note these have o(n) time , space complexity, creating new copy of list content. there no way around linkedlist , arraylist have different structures. using 1 of approaches above speed code accessing .get(i) on linkedlist has linear time, while these use iterators, reducing initialization cost o(n^2) per code o(n).

you seem put lot on emphasys on removing duplicates. peraphs set collection better option use case?