Merge 2 Sorted Linked Lists

Problem Statement

Pattern:

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Solution

ListNode merge(ListNode a, ListNode b) {
	if(a == null) return b;
	if(b == null) return a;
 
	ListNode smaller, larger;
 
	smaller = (a.val <= b.val) ? a : b;
	larger = (b.val >= a.val) ? b : a;
 
	smaller.next = merge(smaller.next, larger);
	return smaller;
}

TC : O(n+m) SC : O(n+m) - stack

Notes