leetcode-链表-2.两数相加

C++版

/**
 * Add Two Numbers
 * 两数相加
*/

class Solution 
{
    
public:
    ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) 
	{
        int x=0, y=0, carry=0, sum=0;
        ListNode *h=NULL, **t=&h;
        
        while (l1!=NULL || l2!=NULL)
		{
            x = getValueAndMoveNext(l1);
            y = getValueAndMoveNext(l2);
            
            sum = carry + x + y;
            
            ListNode *node = new ListNode(sum%10);
            *t = node;
            t = (&node->next);
            
            carry = sum/10;
        }
        
        if (carry > 0) 
		{
            ListNode *node = new ListNode(carry%10);
            *t = node;
        }
        
        return h;
    }
private:
    int getValueAndMoveNext(ListNode* &l)
	{
        int x = 0;
        if (l != NULL)
		{
            x = l->val;
            l = l->next;
        }
        return x;
    }
};

Python版

/**
 * Add Two Numbers
 * 两数相加
*/

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    # maybe standard version
    def _addTwoNumbers(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        p = dummy = ListNode(-1)
        carry = 0
        while l1 and l2:
            p.next = ListNode(l1.val + l2.val + carry)
            carry = p.next.val / 10
            p.next.val %= 10
            p = p.next
            l1 = l1.next
            l2 = l2.next
        
        res = l1 or l2
        while res:
            p.next = ListNode(res.val + carry)
            carry = p.next.val / 10
            p.next.val %= 10
            p = p.next
            res = res.next
        if carry:
            p.next = ListNode(1)
        return dummy.next
    
    # shorter version
    def addTwoNumbers(self, l1, l2):
        p = dummy = ListNode(-1)
        carry = 0
        while l1 or l2 or carry:
            val = (l1 and l1.val or 0) + (l2 and l2.val or 0) + carry
            carry = val / 10
            p.next = ListNode(val % 10)
            l1 = l1 and l1.next
            l2 = l2 and l2.next
            p = p.next
        return dummy.next