Interleaved Linked List - Amazon Top Interview Questions


Problem Statement :


Given two linked lists l0 and l1, return the two linked lists interleaved, starting with l0. If there are leftover nodes in a linked list, they should be added to the end.

Constraints

n ≤ 100,000 where n is the number of nodes in l0
m ≤ 100,000 where m is the number of nodes in l1

Example 1

Input

l0 = [7, 8]
l1 = [1, 2]

Output

[7, 1, 8, 2]

Example 2

Input

l0 = [7, 8]
l1 = [1]

Output

[7, 1, 8]


Solution :



title-img 




                        Solution in C++ :

/**
 * class LLNode {
 *     public:
 *         int val;
 *         LLNode *next;
 * };
 */
LLNode* solve(LLNode* l0, LLNode* l1) {
    if (l0 == NULL) return l1;
    if (l1 == NULL) return l0;
    l0->next = solve(l1, l0->next);
    return l0;
}
                    




                        Solution in Python : 
                            
# class LLNode:
#     def __init__(self, val, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def solve(self, l0, l1):
        head = curr = LLNode(None)
        while l0 and l1:
            curr.next = l0
            l0 = l0.next
            curr = curr.next
            curr.next = l1
            l1 = l1.next
            curr = curr.next
        curr.next = l0 or l1
        return head.next


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