• Remember float('inf') in python.
• Haven't checked zyme in a while, but up to ~45.50.
• https://leetcode.com/problems/merge-two-sorted-lists.
• It's often more convenient to make the recursive call within the function, not in the return clause. Often you want to manipulate the data, or append to the list, or do something before returning the specifics.
• https://leetcode.com/problems/merge-k-sorted-lists. first_iter = True useful in recursion also.
• https://leetcode.com/problems/generate-parentheses. Create all exponential (2^n) permutations, then run verification on them.
• https://leetcode.com/problems/swap-nodes-in-pairs/. Reversing pointer pairs in a linked list. Can't modify values.
• https://leetcode.com/problems/reverse-nodes-in-k-group/. Same, but with general k instead of k=2, alternating every pair.
• https://leetcode.com/problems/remove-duplicates-from-sorted-array/. In-place deduplication in a sorted (thankfully) array. Can't create secondary array, must be constant space complexity.