LeetCode problems in Rust

This repository contains my solutions to LeetCode problems in Rust.

Environment

All problems are solved in VS Code using the LeetCode extension.

Results

#	Title	Solution	Difficulty	Speed score	Memory score	Comments
1	Two Sum	Rust	Easy	23.84 %	68.85 %	Two pointers: one at $i$ and other at $j>i$
9	Palindrome Number	Rust	Easy	69.35 %	17.69 %	Split into digits and converge towards center
13	Roman to Integer	Rust	Easy	100 %	16.15 %	Use mapping for combinations 🤷
14	Longest Common Prefix	Rust	Easy	100 %	55.24 %	Filter remaining strings for containing characters from first one
20	Valid Parentheses	Rust	Easy	50.15 %	19.94 %	Stack
21	Merge Two Sorted Lists	Rust	Easy	6.97%	35.95%	Make list of ordered nodes and collapse it from the end
26	Remove Duplicates from Sorted Array	Rust	Easy	100 %	78.6 %	Make list with uniques and then replace first $n$ entries
27	Remove Element	Rust	Easy	79.48 %	46.72 %	Use two pointers (from start and end)
35	Search Insert Position	Rust	Easy	78.53 %	66.75 %	Check when difference with target changes signs
58	Length of Last Word	Rust	Easy	100 %	40.44 %	Reset counter on whitespace, except for the last character
66	Plus One	Rust	Easy	79.3 %	73.02 %	Split number into digits and do carry overs for digits preceeding urrent index
67	Add Binary	Rust	Easy	26.51 %	26.05 %	Similar to the 66
69	Sqrt(x)	Rust	Easy	100 %	74.03 %	Newton's method for calculating square root
70	Climbing Stairs	Rust	Easy	100 %	37.6 %	Recurrence @ $n-1$ and $n-2$ for $n>1$ (for $n\in\lbrace1,2\rbrace$ return $n$) + memo with HashMap
83	Remove Duplicates from Sorted List	Rust	Easy	9.48 %	88.79 %	List with unique entries and then wrap the values from end
88	Merge Sorted Array	Rust	Easy	83.65 %	47.4 %	Three pointers (for $n$, $m$ and $n+m$)
94	Binary Tree Inorder Traversal	Rust	Easy	100 %	38.52 %	Recursion while enforcing the left-root-right order + clone the nodes accessed as refs and borrowed from RefCells
100	Same Tree	Rust	Easy	100 %	91.67 %	Recursion with match that covers cases for node_1 and node_2 (etc. (None,None) ) that does triple boolean expression comaring lefts, roots and rights
101	Symmetric Tree	Rust	Easy	100 %	29.84 %	Check if (L,R) is (None,None) or (Some,Some) with equal L and R's ($L.R=R.L \land L.L=R.R$)
104	Maximum Depth of Binary Tree	Rust	Easy	100 %	13.27 %	Create vector of ints with depths for each branches and stop at None with pushing the current_depth
108	Convert Sorted Array to Binary Search Tree	Rust	Easy	72.86 %	37.14 %	Recursion, with values split at middle index for left and right branches + calculating middle index w.r.t. to evenness of nums length (substract 1 if even)
110	Balanced Binary Tree	Rust	Easy	100%	16.98%	Height for branch is 1 + max of $H(l)$ and $H(r)$, their differences must be <= 1 AND the $l$ and $r$ must also be balanced (recursion)
111	Minimum Depth of Binary Tree	Rust	Easy	58.24 %	6.59 %	Recursion with running counter for branch, if two branches are present - choose the minimum counter value, if at None return counter - 1
112	Path Sum	Rust	Easy	65.6 %	28.8 %	At each node check if there are available paths on left and/or right. If one is available, go down that path only with recursion, if both - check both and return OR of their respective recursion calls. If there are no paths left, check if sum == target (there is nowhere left to go). At each step increment sum by val
118	Pascal's Triangle	Rust	Easy	84.02 %	58.9 %	Use previous row entries from 0 to len - 1 to calculate inner numbers of next row, append 1s to its start and end. First row is always [1], second one is always [1,1]. Use running row counter.
119	Pascal's Triangle II	Rust	Easy	100 %	47.78 %	Same as 118, but only return the last row
121	Best Time to Buy and Sell Stock	Rust	Easy	89.95 %	68.92 %	Keep track of minimum price and maximum profit (greedy algorithm)
125	Valid Palindrome	Rust	Easy	100 %	34.21 %	Iterate over characters forwards and backwards, while skipping non-alphanumeric characters (while also advancing index), and compare their lowercase ASCII representations
136	Single Number	Rust	Easy	81.45 %	62.16 %	Iterate and keep track on seen numbers, if a number is seen twice - remove it from cache - the result is the remaining entry (there is also a trick with XOR operator): result ^= number
141	Linked List Cycle	-	Easy	NaN	NaN	NOT AVAILABLE IN RUST (due to difficulties with multi-pointers in Rust i.e. borrowing rules)
144	Binary Tree Preorder Traversal	Rust	Easy	100 %	53.97 %	Recursion with root -> left -> right order (the usual None/Some letf-right schtick)
145	Binary Tree Postorder Traversal	Rust	Easy	100 %	45.28 %	Recursion with left -> right -> root order (just change the order in the previous problem of appending values 🤷)
160	Intersection of Two Linked Lists	-	Easy	NaN	NaN	NOT AVAILABLE IN RUST (due to difficulties with multi-pointers in Rust i.e. borrowing rules)