Published Nov 30, 2021
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You are given the heads of two sorted linked lists list1 and list2.
Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists.
Return the head of the merged linked list.
Input: list1 = [1,2,4], list2 = [1,3,4]
Output: [1,1,2,3,4,4]
Input: list1 = [], list2 = []
Output: []
Input: list1 = [], list2 = [0]
Output: [0]
- The number of nodes in both lists is in the range [0, 50].
- -100 <= Node.val <= 100
- Both list1 and list2 are sorted in non-decreasing order.
/**
* Definition for singly-linked list.
* class ListNode {
* val: number
* next: ListNode | null
* constructor(val?: number, next?: ListNode | null) {
* this.val = (val===undefined ? 0 : val)
* this.next = (next===undefined ? null : next)
* }
* }
*/
function mergeTwoLists(list1: ListNode | null, list2: ListNode | null): ListNode | null {
let head: ListNode = new ListNode();
const dummy: ListNode = head;
while(list1 && list2){
if(list1.val <= list2.val){
head.next = new ListNode(list1.val)
list1 = list1.next;
} else {
head.next = new ListNode(list2.val)
list2 = list2.next;
}
head = head.next
}
while(list1){
head.next = new ListNode(list1.val)
list1 = list1.next
head = head.next
}
while(list2){
head.next = new ListNode(list2.val)
list2 = list2.next
head = head.next
}
return dummy.next;
};