题解 | #链表相加(二)#

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head1 ListNode类 
     * @param head2 ListNode类 
     * @return ListNode类
     */
    public ListNode addInList (ListNode head1, ListNode head2) {
        // write code here
        
        LinkedList<Integer> l1 = new LinkedList<>();
        LinkedList<Integer> l2 = new LinkedList<>();
        putData(l1,head1);
        putData(l2,head2);
        
        ListNode Node = null;
        ListNode cur = null ;
        
        int carry = 0;
        while(!l1.isEmpty() || !l2.isEmpty() || carry != 0){
            int x , y ,sum ;
            if(!l1.isEmpty()){
                x = l1.pop();
            }else{
                x = 0;
            }
            if(!l2.isEmpty()){
                y = l2.pop();
            }else{
                y = 0;
            }
            
            sum = x + y + carry ;
            carry = sum / 10;
            sum %= 10 ;
            cur = new ListNode(sum);
            cur.next = Node ;
            Node = cur ;
        }
        return Node ;

    }
    
    public void putData(LinkedList<Integer> s1 , ListNode head){
        if (s1 == null ) s1 = new LinkedList();
        
        while(head != null) {
            s1.push(head.val);
            head = head.next ;
        }
        
    }

}