[leetcode][2] Add Two Numbers
Posted ekoeko
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2. Add Two Numbers
You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
You may assume the two numbers do not contain any leading zero, except the number 0 itself.
Example:
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.
解析
很简单用链表表示数字相加,注意进位就行了
参考答案(自己写的)
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode head = new ListNode(0);
ListNode index = head;
int move = 0;
while(l1 != null || l2 != null) {
int value = move;
if (l1 != null) {
value += l1.val;
l1 = l1.next;
}
if (l2 != null) {
value += l2.val;
l2 = l2.next;
}
if (value >= 10) {
move = 1;
value = value - 10;
} else {
move = 0;
}
ListNode newNode = new ListNode(value);
index.next = newNode;
index = newNode;
}
if (move != 0) {
index.next = new ListNode(1);
}
return head.next;
}
}
注意点原来我用的是value = value%10,这样效率很低,其实value的值不会超过10,所以直接value = value - 10就行了。
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