universal-dich2

import kotlinx.atomicfu.AtomicRef;


public class Solution implements AtomicCounter {
    private final ThreadLocal<Node> last;
    private final Node root; // root is initial value for last

    public Solution(){
        this.root = new Node();
        this.last = ThreadLocal.withInitial(() -> root);
        /*this.last = new ThreadLocal<>();
        this.last.set(root);*/
    }

    public int getAndAdd(int x) {
        int res;
        while(true){
            int upd = last.get().val.getValue();
            //System.out.println("Old: " + upd);
            res = upd + x;
            Node node = new Node();
            node.val.setValue(res);
            /*ThreadLocal<Node> node = ThreadLocal.withInitial(() -> new Node());
            node.get().val.setValue(upd);*/
            last.set(last.get().next.decide(node));
            if (last.get() == node){
                break;
            }
        }
        //System.out.println("Final res: " + res);
        return res;
    }

    private static class Node {
        private final AtomicRef<Integer> val = new AtomicRef<>(0);
        private final Consensus<Node> next = new Consensus<>();
    }
}