2. Add Two Numbers
2. Add Two Numbers
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.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
1 /** 2 * Definition for singly-linked list. 3 * function ListNode(val) { 4 * this.val = val; 5 * this.next = null; 6 * } 7 */ 8 /** 9 * @param {ListNode} l1 10 * @param {ListNode} l2 11 * @return {ListNode} 12 */ 13 var addTwoNumbers = function(l1, l2) { 14 15 //这种累加的题目，主要是注意进位 16 var carry = 0; 17 //头指针 18 var head = new ListNode(0); 19 20 var res = head; 21 22 //保证两个都有值 就累加，否者就直接添加 23 while(l1&&l2){ 24 25 //一开始就加上carry,默认是0 26 var val = l1.val + l2.val + carry; 27 val - 9 > 0 ? carry = 1 : carry = 0; 28 29 val %= 10; 30 var node = new ListNode(val); 31 res.next = node; 32 33 res = node; 34 35 l1 = l1.next; 36 l2 = l2.next; 37 38 } 39 40 //处理 2->3->4 + 2->3 这种 41 while(l1){ 42 43 var val = l1.val + carry; 44 val - 9 > 0 ? carry = 1 : carry = 0; 45 val %= 10; 46 var node = new ListNode(val); 47 res.next = node; 48 49 res = node; 50 l1 = l1.next; 51 52 } 53 54 while(l2){ 55 56 var val = l2.val + carry; 57 val - 9 > 0 ? carry = 1 : carry = 0; 58 val %= 10; 59 var node = new ListNode(val); 60 res.next = node; 61 62 res = node; 63 l2 = l2.next; 64 } 65 66 //注意处理最后一个进位 比如 5,5 输出0->1 67 if(carry){ 68 var node = new ListNode(carry); 69 res.next = node; 70 71 res = node; 72 } 73 74 return head.next; 75 76 77 };
