Grind Collection in Python: Tested Solutions

Grind holds 169 problems (40 Easy, 103 Medium, 26 Hard). The extended Grind collection is a superset of Grind 75 for longer prep timelines, with broader coverage of the same interview patterns. Every problem generates a Python practice environment with a parametrized pytest suite and a tested reference solution. This collection includes every problem in Grind 75. Generate the whole collection into the current directory:

lcpy gen -t grind

#	Problem	Difficulty	Solution
1	Two Sum	Easy	solution.py
2	Add Two Numbers	Medium	solution.py
3	Longest Substring Without Repeating Characters	Medium	solution.py
4	Median of Two Sorted Arrays	Hard	solution.py
5	Longest Palindromic Substring	Medium	solution.py
7	Reverse Integer	Medium	solution.py
8	String to Integer (atoi)	Medium	solution.py
9	Palindrome Number	Easy	solution.py
11	Container With Most Water	Medium	solution.py
13	Roman to Integer	Easy	solution.py
14	Longest Common Prefix	Easy	solution.py
15	3Sum	Medium	solution.py
16	3Sum Closest	Medium	solution.py
17	Letter Combinations of a Phone Number	Medium	solution.py
19	Remove Nth Node From End of List	Medium	solution.py
20	Valid Parentheses	Easy	solution.py
21	Merge Two Sorted Lists	Easy	solution.py
22	Generate Parentheses	Medium	solution.py
23	Merge k Sorted Lists	Hard	solution.py
24	Swap Nodes in Pairs	Medium	solution.py
25	Reverse Nodes in k-Group	Hard	solution.py
31	Next Permutation	Medium	solution.py
32	Longest Valid Parentheses	Hard	solution.py
33	Search in Rotated Sorted Array	Medium	solution.py
36	Valid Sudoku	Medium	solution.py
37	Sudoku Solver	Hard	solution.py
39	Combination Sum	Medium	solution.py
41	First Missing Positive	Hard	solution.py
42	Trapping Rain Water	Hard	solution.py
46	Permutations	Medium	solution.py
48	Rotate Image	Medium	solution.py
49	Group Anagrams	Medium	solution.py
50	Pow(x, n)	Medium	solution.py
51	N-Queens	Hard	solution.py
53	Maximum Subarray	Medium	solution.py
54	Spiral Matrix	Medium	solution.py
55	Jump Game	Medium	solution.py
56	Merge Intervals	Medium	solution.py
57	Insert Interval	Medium	solution.py
61	Rotate List	Medium	solution.py
62	Unique Paths	Medium	solution.py
67	Add Binary	Easy	solution.py
70	Climbing Stairs	Easy	solution.py
73	Set Matrix Zeroes	Medium	solution.py
74	Search a 2D Matrix	Medium	solution.py
75	Sort Colors	Medium	solution.py
76	Minimum Window Substring	Hard	solution.py
78	Subsets	Medium	solution.py
79	Word Search	Medium	solution.py
84	Largest Rectangle in Histogram	Hard	solution.py
91	Decode Ways	Medium	solution.py
98	Validate Binary Search Tree	Medium	solution.py
100	Same Tree	Easy	solution.py
101	Symmetric Tree	Easy	solution.py
102	Binary Tree Level Order Traversal	Medium	solution.py
103	Binary Tree Zigzag Level Order Traversal	Medium	solution.py
104	Maximum Depth of Binary Tree	Easy	solution.py
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	solution.py
108	Convert Sorted Array to Binary Search Tree	Easy	solution.py
110	Balanced Binary Tree	Easy	solution.py
113	Path Sum II	Medium	solution.py
121	Best Time to Buy and Sell Stock	Easy	solution.py
124	Binary Tree Maximum Path Sum	Hard	solution.py
125	Valid Palindrome	Easy	solution.py
127	Word Ladder	Hard	solution.py
128	Longest Consecutive Sequence	Medium	solution.py
133	Clone Graph	Medium	solution.py
134	Gas Station	Medium	solution.py
136	Single Number	Easy	solution.py
139	Word Break	Medium	solution.py
141	Linked List Cycle	Easy	solution.py
143	Reorder List	Medium	solution.py
146	LRU Cache	Medium	solution.py
148	Sort List	Medium	solution.py
150	Evaluate Reverse Polish Notation	Medium	solution.py
152	Maximum Product Subarray	Medium	solution.py
153	Find Minimum in Rotated Sorted Array	Medium	solution.py
155	Min Stack	Medium	solution.py
169	Majority Element	Easy	solution.py
179	Largest Number	Medium	solution.py
189	Rotate Array	Medium	solution.py
190	Reverse Bits	Easy	solution.py
191	Number of 1 Bits	Easy	solution.py
198	House Robber	Medium	solution.py
199	Binary Tree Right Side View	Medium	solution.py
200	Number of Islands	Medium	solution.py
206	Reverse Linked List	Easy	solution.py
207	Course Schedule	Medium	solution.py
208	Implement Trie (Prefix Tree)	Medium	solution.py
210	Course Schedule II	Medium	solution.py
211	Design Add and Search Words Data Structure	Medium	solution.py
212	Word Search II	Hard	solution.py
215	Kth Largest Element in an Array	Medium	solution.py
217	Contains Duplicate	Easy	solution.py
221	Maximal Square	Medium	solution.py
224	Basic Calculator	Hard	solution.py
226	Invert Binary Tree	Easy	solution.py
227	Basic Calculator II	Medium	solution.py
230	Kth Smallest Element in a BST	Medium	solution.py
232	Implement Queue using Stacks	Easy	solution.py
234	Palindrome Linked List	Easy	solution.py
235	Lowest Common Ancestor of a Binary Search Tree	Medium	solution.py
236	Lowest Common Ancestor of a Binary Tree	Medium	solution.py
238	Product of Array Except Self	Medium	solution.py
239	Sliding Window Maximum	Hard	solution.py
242	Valid Anagram	Easy	solution.py
252	Meeting Rooms	Easy	solution.py
253	Meeting Rooms II	Medium	solution.py
261	Graph Valid Tree	Medium	solution.py
268	Missing Number	Easy	solution.py
269	Alien Dictionary	Hard	solution.py
271	Encode and Decode Strings	Medium	solution.py
278	First Bad Version	Easy	solution.py
283	Move Zeroes	Easy	solution.py
285	Inorder Successor in BST	Medium	solution.py
287	Find the Duplicate Number	Medium	solution.py
295	Find Median from Data Stream	Hard	solution.py
297	Serialize and Deserialize Binary Tree	Hard	solution.py
300	Longest Increasing Subsequence	Medium	solution.py
310	Minimum Height Trees	Medium	solution.py
322	Coin Change	Medium	solution.py
323	Number of Connected Components in an Undirected Graph	Medium	solution.py
328	Odd Even Linked List	Medium	solution.py
329	Longest Increasing Path in a Matrix	Hard	solution.py
336	Palindrome Pairs	Hard	solution.py
338	Counting Bits	Easy	solution.py
362	Design Hit Counter	Medium	solution.py
377	Combination Sum IV	Medium	solution.py
380	Insert Delete GetRandom O(1)	Medium	solution.py
383	Ransom Note	Easy	solution.py
394	Decode String	Medium	solution.py
409	Longest Palindrome	Easy	solution.py
416	Partition Equal Subset Sum	Medium	solution.py
417	Pacific Atlantic Water Flow	Medium	solution.py
424	Longest Repeating Character Replacement	Medium	solution.py
435	Non-overlapping Intervals	Medium	solution.py
437	Path Sum III	Medium	solution.py
438	Find All Anagrams in a String	Medium	solution.py
525	Contiguous Array	Medium	solution.py
528	Random Pick with Weight	Medium	solution.py
542	01 Matrix	Medium	solution.py
543	Diameter of Binary Tree	Easy	solution.py
560	Subarray Sum Equals K	Medium	solution.py
572	Subtree of Another Tree	Easy	solution.py
588	Design In-Memory File System	Hard	solution.py
621	Task Scheduler	Medium	solution.py
632	Smallest Range Covering Elements from K Lists	Hard	solution.py
658	Find K Closest Elements	Medium	solution.py
662	Maximum Width of Binary Tree	Medium	solution.py
692	Top K Frequent Words	Medium	solution.py
704	Binary Search	Easy	solution.py
721	Accounts Merge	Medium	solution.py
733	Flood Fill	Easy	solution.py
735	Asteroid Collision	Medium	solution.py
739	Daily Temperatures	Medium	solution.py
759	Employee Free Time	Hard	solution.py
787	Cheapest Flights Within K Stops	Medium	solution.py
815	Bus Routes	Hard	solution.py
844	Backspace String Compare	Easy	solution.py
863	All Nodes Distance K in Binary Tree	Medium	solution.py
876	Middle of the Linked List	Easy	solution.py
895	Maximum Frequency Stack	Hard	solution.py
973	K Closest Points to Origin	Medium	solution.py
977	Squares of a Sorted Array	Easy	solution.py
981	Time Based Key-Value Store	Medium	solution.py
994	Rotting Oranges	Medium	solution.py
1197	Minimum Knight Moves	Medium	solution.py
1235	Maximum Profit in Job Scheduling	Hard	solution.py
1730	Shortest Path to Get Food	Medium	solution.py

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Grind Collection in Python: Tested Solutions