Leet code - 2. Add Two Number - Java

leetcode.com/problems/add-two-numbers/

Add Two Numbers - LeetCode

 

 

이전에 C++로 풀었던 것을 자바로 다시 한번 복기할겸 풀었다.

 

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode head = new ListNode();
        ListNode cur_pointer = head;
        
        int carry = 0;
        
        while(l1 != null && l2 != null) {
            int added_val = l1.val + l2.val + carry;
            
            if(carry > 0)
                carry = 0;
            
            
            if(added_val >= 10) {
                added_val %= 10;
                carry = 1;
            }
            
            cur_pointer.next = new ListNode(added_val);
            
            cur_pointer = cur_pointer.next;
            l1 = l1.next;
            l2 = l2.next;
        }
        
        while(l1 != null) {
            int added_val = l1.val + carry;
            
            if(carry > 0)
                --carry;
                
            if(added_val >= 10) {
                added_val %= 10;
                carry = 1;
            }
            
            cur_pointer.next = new ListNode(added_val);
            
            cur_pointer = cur_pointer.next;
            l1 = l1.next;
        }
        
        while(l2 != null) {
            int added_val = l2.val + carry;
            
            if(carry > 0)
                --carry;
            
            if(added_val >= 10) {
                added_val %= 10;
                carry = 1;
            }
            
            cur_pointer.next = new ListNode(added_val);
            cur_pointer = cur_pointer.next;
            l2 = l2.next;
        }
        
        while(carry > 0) {
            cur_pointer.next = new ListNode(carry);
            carry = 0;
        }
        
        return head.next;
    }
}

 

다음과 같이 3항 연산자를 이용해 간단하게 풀이도 할 수 있는듯하다