Add two non-empty linked lists representing two non-negative integers

December 4, 2017December 4, 2017 by omt

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

(2 -> 4 -> 3) + (5 -> 6 -> 4)

Output : 7->0->8

package com.omt.learn.algo;

import java.util.Calendar;

class ListNode{
	
	int val;
	ListNode next;
	public ListNode(int val) {
		this.val = val;
	}
}

public class AddTwoNumbers {
	
	
	public static ListNode addTwoNumbers(ListNode l1, ListNode l2) {
		
		int sum = l1.val+l2.val;
		int remaining = sum > 9?1:0;
		sum = sum%10;
		ListNode listNode = new ListNode(sum);
		ListNode firstNode = listNode;
		while(l1.next != null || l2.next != null) {
			sum = 0;
			
			if(l1.next != null) {
				l1 = l1.next;
				sum = l1.val;
			}
			if(l2.next != null) {
				l2 = l2.next;
				sum+= l2.val;
			}
			sum += remaining;
			remaining = sum > 9?1:0;
			sum = sum%10;
			listNode.next = new ListNode(sum);
			listNode = listNode.next;
		}
		
		
		if(remaining > 0) {
			listNode.next = new ListNode(remaining);
		}
		
		return firstNode;
	}

	
	public static void main(String...strings) {
		ListNode l1 = createListNode("2->4->3");
		ListNode l2 = createListNode("5->6->4");
		ListNode sum = addTwoNumbers(l1, l2);
		System.out.println("");
		System.out.print(sum.val);
		while(sum.next != null) {
			System.out.print("->"+sum.next.val);
			sum = sum.next;
		}
		
	}
	
	private  static ListNode createListNode(String data) {
		String[] array = data.split("->");
		ListNode listNode = null;
		for(String digit : array) {
			if(listNode == null) {
				listNode = new ListNode(Integer.parseInt(digit.trim()));
			} else {
				
				ListNode lastOne = listNode;
				while(lastOne.next != null) {
					lastOne = lastOne.next;
				}
				
				lastOne.next  = new ListNode(Integer.parseInt(digit.trim()));
			}
		}
		return listNode;
	}
}

package com.omt.learn.algo;

import java.util.Calendar;

class ListNode{

int val;

ListNode next;

public ListNode(int val) {

this.val = val;

}

public class AddTwoNumbers {

public static ListNode addTwoNumbers(ListNode l1, ListNode l2) {

int sum = l1.val+l2.val;

int remaining = sum > 9?1:0;

sum = sum%10;

ListNode listNode = new ListNode(sum);

ListNode firstNode = listNode;

while(l1.next != null || l2.next != null) {

sum = 0;

if(l1.next != null) {

l1 = l1.next;

sum = l1.val;

}

if(l2.next != null) {

l2 = l2.next;

sum+= l2.val;

}

sum += remaining;

remaining = sum > 9?1:0;

sum = sum%10;

listNode.next = new ListNode(sum);

listNode = listNode.next;

}

if(remaining > 0) {

listNode.next = new ListNode(remaining);

}

return firstNode;

}

public static void main(String...strings) {

ListNode l1 = createListNode("2->4->3");

ListNode l2 = createListNode("5->6->4");

ListNode sum = addTwoNumbers(l1, l2);

System.out.println("");

System.out.print(sum.val);

while(sum.next != null) {

System.out.print("->"+sum.next.val);

sum = sum.next;

}

private static ListNode createListNode(String data) {

String[] array = data.split("->");

ListNode listNode = null;

for(String digit : array) {

if(listNode == null) {

listNode = new ListNode(Integer.parseInt(digit.trim()));

} else {

ListNode lastOne = listNode;

while(lastOne.next != null) {

lastOne = lastOne.next;

}

lastOne.next = new ListNode(Integer.parseInt(digit.trim()));

}

return listNode;

}