Day 100.2.txt

1669. Merge In Between Linked Lists

You are given two linked lists: list1 and list2 of sizes n and m respectively.

Remove list1's nodes from the ath node to the bth node, and put list2 in their place.

The blue edges and nodes in the following figure incidate the result:


Build the result list and return its head.

 

Example 1:


Input: list1 = [0,1,2,3,4,5], a = 3, b = 4, list2 = [1000000,1000001,1000002]
Output: [0,1,2,1000000,1000001,1000002,5]
Explanation: We remove the nodes 3 and 4 and put the entire list2 in their place. The blue edges and nodes in the above figure indicate the result.
Example 2:


Input: list1 = [0,1,2,3,4,5,6], a = 2, b = 5, list2 = [1000000,1000001,1000002,1000003,1000004]
Output: [0,1,1000000,1000001,1000002,1000003,1000004,6]
Explanation: The blue edges and nodes in the above figure indicate the result.
 

Constraints:

3 <= list1.length <= 104
1 <= a <= b < list1.length - 1
1 <= list2.length <= 104




class Solution {
    public ListNode mergeInBetween(ListNode l1, int a, int b, ListNode l2) {
        ListNode ptr=l1;
        for(int i=0;i<a-1;i++)
        {
            ptr=ptr.next;
        }
        ListNode k=ptr;
        for(int i=a;i<=b;i++)
        {
            k=k.next;
        }
        ptr.next=l2;
        for(;l2.next!=null;l2=l2.next);
        l2.next=k.next;
        return l1;
    }
}