Add Two Numbers
You are given two linked lists representing two non-negative numbers. 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.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
比较简单，还是用Java编写，一次过O(∩_∩)O
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * int val; 5 * ListNode next; 6 * ListNode(int x) { 7 * val = x; 8 * next = null; 9 * } 10 * } 11 */ 12 public class Solution { 13 public ListNode addTwoNumbers(ListNode l1, ListNode l2) { 14 int s = l1.val+l2.val,carry = 0; 15 if(s>9) 16 { 17 s=s-10; 18 carry=1; 19 } 20 ListNode sum = new ListNode(s); 21 ListNode next= sum; 22 while(l1.next!=null&&l2.next!=null) 23 { 24 s=l1.next.val+l2.next.val+carry; 25 carry=0; 26 if(s>9) 27 { 28 s=s-10; 29 carry=1; 30 } 31 next.next=new ListNode(s); 32 next=next.next; 33 l1=l1.next; 34 l2=l2.next; 35 } 36 while(l1.next==null&&l2.next!=null) 37 { 38 s=l2.next.val+carry; 39 carry=0; 40 if(s>9) 41 { 42 s=s-10; 43 carry=1; 44 } 45 next.next=new ListNode(s); 46 next=next.next; 47 l2=l2.next; 48 } 49 while(l1.next!=null&&l2.next==null) 50 { 51 s=l1.next.val+carry; 52 carry=0; 53 if(s>9) 54 { 55 s=s-10; 56 carry=1; 57 } 58 next.next=new ListNode(s); 59 next=next.next; 60 l1=l1.next; 61 } 62 if(carry==1) 63 next.next=new ListNode(carry); 64 65 return sum; 66 } 67 }
运行时间排最后。。因为最近在学Java。查了一下其他解决办法。下面那个是445ms的，比我的快了1ms，虽然时间差不多，不过看着就比我那个好多了。╮(╯▽╰)╭
1 public class Solution { 2 public ListNode addTwoNumbers(ListNode l1, ListNode l2) { 3 int carry =0; 4 5 ListNode newHead = new ListNode(0); 6 ListNode p1 = l1, p2 = l2, p3=newHead; 7 8 while(p1 != null || p2 != null){ 9 if(p1 != null){ 10 carry += p1.val; 11 p1 = p1.next; 12 } 13 14 if(p2 != null){ 15 carry += p2.val; 16 p2 = p2.next; 17 } 18 19 p3.next = new ListNode(carry%10); 20 p3 = p3.next; 21 carry /= 10; 22 } 23 24 if(carry==1) 25 p3.next=new ListNode(1); 26 27 return newHead.next; 28 } 29 }
参考来源：http://www.programcreek.com/2012/12/add-two-numbers/