目录
LeetCode-21题
将两个升序链表合并成一个新的升序链表并返回
java
class Solution {
public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
if (list1 == null)
return list2;
if (list2 == null)
return list1;
ListNode dummyHead = new ListNode();
ListNode curr = dummyHead;
// 双指针
ListNode p1 = list1;
ListNode p2 = list2;
while (p1 != null && p2 != null) {
// 链入节点值较小的节点
if (p1.val < p2.val) {
curr.next = p1;
p1 = p1.next;
} else {
curr.next = p2;
p2 = p2.next;
}
curr = curr.next;
}
// 处理剩余节点
if (p1 != null)
curr.next = p1;
if (p2 != null)
curr.next = p2;
return dummyHead.next;
}
private static class ListNode {
int val;
ListNode next;
ListNode() {
}
ListNode(int val) {
this.val = val;
}
ListNode(int val, ListNode next) {
this.val = val;
this.next = next;
}
}
}