2. 两数相加

墨蓝 2023-10-05 21:29 2阅读 0赞

给你两个 **非空** 的链表，表示两个非负的整数。它们每位数字都是按照 **逆序** 的方式存储的，并且每个节点只能存储 **一位** 数字。

请你将两个数相加，并以相同形式返回一个表示和的链表。

你可以假设除了数字 0 之外，这两个数都不会以 0 开头。

**示例 1：**

![7d87baa243f73bac7930b19529e847c7.png][]

输入：l1 = [2,4,3], l2 = [5,6,4]
    输出：[7,0,8]
    解释：342 + 465 = 807.

**示例 2：**

输入：l1 = [0], l2 = [0]
    输出：[0]

**示例 3：**

输入：l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
    输出：[8,9,9,9,0,0,0,1]

**提示：**

*  每个链表中的节点数在范围 `[1, 100]` 内
 *  `0 <= Node.val <= 9`
 *  题目数据保证列表表示的数字不含前导零

package Solution2;
    
    class Solution {
    	public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
    		ListNode dummy0 = new ListNode(-1);
    		ListNode s0 = dummy0;
    
    		ListNode dummy1 = new ListNode(-1);
    		ListNode s1 = dummy1;
    
    		ListNode dummy2 = new ListNode(-1);
    		ListNode s2 = dummy2;
    
    		ListNode curr1 = l1;
    		ListNode curr2 = l2;
    
    		int temp = 0;
    		int sum = 0;
    		while (curr1 != null || curr2 != null) {
    			if (curr1 != null && curr2 != null) {
    				sum = curr1.val + curr2.val + temp;
    
    				temp = sum / 10;
    				sum = sum % 10;
    
    				ListNode t = new ListNode(sum);
    				s0.next = t;
    				s1.next = curr1;
    				s1 = s1.next;
    				s2.next = curr2;
    				s2 = s2.next;
    				curr1 = curr1.next;
    				curr2 = curr2.next;
    				s0 = s0.next;
    			} else if (curr1 != null && curr2 == null) {
    				sum = curr1.val + temp;
    				temp = sum / 10;
    				sum = sum % 10;
    
    				ListNode t = new ListNode(sum);
    				s0.next = t;
    				s1.next = curr1;
    				s1 = s1.next;
    				curr1 = curr1.next;
    				s0 = s0.next;
    
    			} else if (curr1 == null && curr2 != null) {
    				sum = curr2.val + temp;
    				temp = sum / 10;
    				sum = sum % 10;
    
    				ListNode t = new ListNode(sum);
    				s0.next = t;
    				s2.next = curr2;
    				s2 = s2.next;
    				curr2 = curr2.next;
    				s0 = s0.next;
    
    			}
    
    		}
    		if (temp == 1) {
    			ListNode t = new ListNode(1);
    			s0.next = t;
    		}
    		return dummy0.next;
    
    	}
    
    	void printList(ListNode node) {
    		while (node != null) {
    			System.out.print(node.val + " ");
    			node = node.next;
    		}
    	}
    
    	public static void main(String[] args) {
    
    		Solution sol = new Solution();
    
    		ListNode list1 = new ListNode(2);
    		list1.next = new ListNode(4);
    		list1.next.next = new ListNode(6);
    
    		ListNode list2 = new ListNode(5);
    		list2.next = new ListNode(6);
    		list2.next.next = new ListNode(4);
    
    		sol.printList(sol.addTwoNumbers(list1, list2));
    
    	}
    
    }

[7d87baa243f73bac7930b19529e847c7.png]: https://img-blog.csdnimg.cn/img_convert/7d87baa243f73bac7930b19529e847c7.png