[Leetcode#2] ADD Numbers

The question:

Given an array of integers, find the numbers such that they add up to a specific target number.

The function twosum should return indices of the numbers such that they add up to the target, where index1 must is Les S than Index2. Please note that your returned answers (both Index1 and INDEX2) is not zero-based.

You may assume this each input would has exactly one solution.

Input:numbers={2, 7, one, A, target=9
Output:index1=1, index2=2

Analysis:

This question was simple,

Digit = (L1_current.value + l2_current.value + carry)% 10;

Carry = (L1_current.value + l2_current.value + carry)% 10;

Corner Case:

Apparently, we would do the above computation in the while loop:while (l1_current! = NULL | | l2_current).

When we exit from the loop, there could are a situation that carry are 1, while all nodes in List 1 and List 2 have already b Een scanned.

We need to tackle this situation by adding following lines:

if // Take care , there might is a additional carry in the last digit            New ListNode (1);             = NewNode;             = Temp.next;}

My Solution:

/*** Definition for singly-linked list. * public class ListNode {* int val; * ListNode Next; * ListNode (int X) {* val = x; * next = NULL; *} *}*/ Public classSolution { PublicListNode addtwonumbers (listnode L1, ListNode L2) {listnode LR=NewListNode (0); ListNode Temp= LR;//used to remember the current scan position, Note:this are dummpy head for keeping loop invariant!ListNode l1_current = L1;//Not dumy headListNode l2_current =L2; ListNode NewNode=NULL; intcarry = 0;//set the initial carry into zero         while(L1_current! =NULL|| L2_current! =NULL) {                       if(L1_current = =NULL&& l2_current! =NULL) {NewNode=NewListNode ((l2_current.val + carry)% 10); Carry= (L2_current.val + carry)/10;//there is no carry for next digit (next upper digit)L2_current =L2_current.next; //continue;           }                      if(L2_current = =NULL&& l1_current! =NULL) {NewNode=NewListNode ((l1_current.val + carry)% 10); Carry= (L1_current.val + carry)/10; L1_current=L1_current.next; //continue;            }                      if(L1_current! =NULL&& l2_current! =NULL) {NewNode=NewListNode ((L1_current.val + l2_current.val + carry)% 10); Carry= (L1_current.val + l2_current.val + carry)/10; L1_current=L1_current.next; L2_current=L2_current.next; //continue the continue would jump over the temp~~~~ careful!} temp.next= NewNode;//The head of the result list is recored in LRtemp = Temp.next;//move the scanner to the next position        }                if(Carry = = 1) {//Take care , there might is a additional carry in the last digitNewNode =NewListNode (1); Temp.next=NewNode; Temp=Temp.next; }                returnLr.next; }}

[Leetcode#2] ADD Numbers