首页 > itarticle > add two numbers Solution

add two numbers Solution

admin 11月 13, 2020 0

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.

Example

1
2
3

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

Solution

思路

这个题是一道使用链表进行整数加法运算的题。
需要考虑进位和两个链表长度不同的情况。
在最后需要对末尾进行特殊操作。即最后一位进位为1。

实现

class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        int newValue = 0;
        int nextNewValue = 0;
        int num1,num2 = 0;
        ListNode result = new ListNode(0);
        ListNode temp = result;
        while(l1 != null || l2 != null){
            num1 = l1 != null ? l1.val:0;
            num2 = l2 != null ? l2.val:0;
            newValue = num1 + num2 + nextNewValue;
            nextNewValue = 0;
            if(newValue >=10){
                newValue = newValue - 10;
                nextNewValue ++;
            }
            //temp.val = newValue;
            temp.next = new ListNode(newValue);
            temp = temp.next;
            if(l1 != null)
                l1 = l1.next;
            if(l2 != null)
                l2 = l2.next;
        }
        if(nextNewValue == 1){
            temp.next = new ListNode(1);
        }
        return result.next;
    }
}