2.两个链表同一节点两数相加

/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode() {} * ListNode(int val) { this.val = val; } * ListNode(int val, ListNode next) { this.val = val; this.next = next; } * } */ class Solution { public ListNode addTwoNumbers(ListNode l1, ListNode l2) { ListNode head = new ListNode(0); //新链表的头结点 ListNode cur = head; //用于移动 int carry = 0; //存进位的 while(l1 != null || l2 != null){ int x = l1 != null ? l1.val : 0; int y = l2 != null ? l2.val : 0; int sum = x+y+carry; carry = sum/10;//大于10就取进位 sum = sum%10; //个位 cur.next = new ListNode(sum); cur = cur.next; //后移 if(l1 != null ){ l1 = l1.next; } if(l2 != null){ l2 = l2.next; } } if(carry == 1){ cur.next = new ListNode(carry); } return head.next; } }