LeetCode:2. 两数相加


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两数相加

前置声明

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两数相加

O(n)复杂度

按题意来，两个链遍历，取个位，进十位就行了。

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/**
 * 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 p = new ListNode(0);  
        ListNode cur = p;  
        int pp = 0;  
        while (l1 != null || l2 != null || pp != 0) {  
            int s1 = l1 != null ? l1.val : 0;  
            int s2 = l2 != null ? l2.val : 0;  
            int add = s1 + s2 + pp;  
            pp = add >= 10 ? 1 : 0;  
            add = add >= 10 ? add - 10 : add;  
            cur.next = new ListNode(add);  
            cur = cur.next;  
            if (l1 != null) {  
                l1 = l1.next;  
            }  
            if (l2 != null) {  
                l2 = l2.next;  
            }  
        }  
        return p.next;  
    }  
}
a u t h o r

姓王者

p u b l i c

2024/09/22 21:08:27 CST

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