AggregateAtZeroNode.java

package co.in.shoonya.abc.prep.ds.lists;

import co.in.shoonya.abc.prep.ds.lists.ds.ListNode;

public class AggregateAtZeroNode {

    public static void main(String[] args) {
        ListNode<Integer> l1 = new ListNode<Integer>(1);
        l1.setNext(new ListNode<Integer>(4));
        l1.getNext().setNext(new ListNode<Integer>(0));
        l1.getNext().getNext().setNext(new ListNode<Integer>(0));
        l1.getNext().getNext().getNext().setNext(new ListNode<Integer>(2));
        l1.getNext().getNext().getNext().getNext().setNext(new ListNode<Integer>(2));
        l1.getNext().getNext().getNext().getNext().getNext().setNext(new ListNode<Integer>(0));
        l1.getNext().getNext().getNext().getNext().getNext().getNext().setNext(new ListNode<Integer>(7));
        System.out.println("aggregateAtZero::b4\t" + l1);
        System.out.println("aggregateAtZero::4\t" + aggregateAtZero(l1));
    }

    private static ListNode<Integer> aggregateAtZero(ListNode<Integer> input) {
        int currSum = 0;
        int marker = 0;
        ListNode<Integer> prev = input;
        ListNode<Integer> curr = input;
        while (curr != null) {
            currSum += curr.getData();
            if (curr.getData() == marker) {
                prev.setData(currSum);
                prev.setNext(curr.getNext());
                prev = prev.getNext();
                currSum = 0;
            }
            curr = curr.getNext();
        }
        return input;
    }
}