golang刷leetcode 技巧（25）链表求和

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
  if l1==nil{
      return l2
  }
  if l2==nil{
      return l1
  }
  r:=new(ListNode)
  tr:=r
  t1:=l1
  t2:=l2
  flag:=0

  tr.Val=(t1.Val+t2.Val+flag)%10
  flag=(t1.Val+t2.Val+flag)/10
  for t1.Next!=nil && t2.Next!=nil{
      tr.Next=new(ListNode)
      tr=tr.Next
      t1=t1.Next
      t2=t2.Next

        tr.Val=(t1.Val+t2.Val+flag)%10
        flag=(t1.Val+t2.Val+flag)/10      
  }

  for t1.Next!=nil{
            tr.Next=new(ListNode)
      tr=tr.Next
      t1=t1.Next
      tr.Val=(t1.Val+flag)%10
      flag=(t1.Val+flag)/10   
  }

  for t2.Next!=nil{
      tr.Next=new(ListNode)
      tr=tr.Next
      t2=t2.Next
       tr.Val=(t2.Val+flag)%10
        flag=(t2.Val+flag)/10   
  }

  if flag!=0{
            tr.Next=new(ListNode)
      tr=tr.Next
      tr.Val=flag
  }

return r
}