Grind 75 in Python with Tested Solutions

Grind 75 holds 75 problems (23 Easy, 43 Medium, 9 Hard). Grind 75 is the essential-75 list from Tech Interview Handbook, ordered by a week-by-week study plan built around pattern coverage and time budget. Every problem generates a Python practice environment with a parametrized pytest suite and a tested reference solution. Generate the whole collection into the current directory:

lcpy gen -t grind-75

#	Problem	Difficulty	Solution
1	Two Sum	Easy	solution.py
3	Longest Substring Without Repeating Characters	Medium	solution.py
5	Longest Palindromic Substring	Medium	solution.py
8	String to Integer (atoi)	Medium	solution.py
11	Container With Most Water	Medium	solution.py
15	3Sum	Medium	solution.py
17	Letter Combinations of a Phone Number	Medium	solution.py
20	Valid Parentheses	Easy	solution.py
21	Merge Two Sorted Lists	Easy	solution.py
23	Merge k Sorted Lists	Hard	solution.py
33	Search in Rotated Sorted Array	Medium	solution.py
39	Combination Sum	Medium	solution.py
42	Trapping Rain Water	Hard	solution.py
46	Permutations	Medium	solution.py
53	Maximum Subarray	Medium	solution.py
54	Spiral Matrix	Medium	solution.py
56	Merge Intervals	Medium	solution.py
57	Insert Interval	Medium	solution.py
62	Unique Paths	Medium	solution.py
67	Add Binary	Easy	solution.py
70	Climbing Stairs	Easy	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
98	Validate Binary Search Tree	Medium	solution.py
102	Binary Tree 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
110	Balanced Binary Tree	Easy	solution.py
121	Best Time to Buy and Sell Stock	Easy	solution.py
125	Valid Palindrome	Easy	solution.py
127	Word Ladder	Hard	solution.py
133	Clone Graph	Medium	solution.py
139	Word Break	Medium	solution.py
141	Linked List Cycle	Easy	solution.py
146	LRU Cache	Medium	solution.py
150	Evaluate Reverse Polish Notation	Medium	solution.py
155	Min Stack	Medium	solution.py
169	Majority Element	Easy	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
217	Contains Duplicate	Easy	solution.py
224	Basic Calculator	Hard	solution.py
226	Invert Binary Tree	Easy	solution.py
230	Kth Smallest Element in a BST	Medium	solution.py
232	Implement Queue using Stacks	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
242	Valid Anagram	Easy	solution.py
278	First Bad Version	Easy	solution.py
295	Find Median from Data Stream	Hard	solution.py
297	Serialize and Deserialize Binary Tree	Hard	solution.py
310	Minimum Height Trees	Medium	solution.py
322	Coin Change	Medium	solution.py
383	Ransom Note	Easy	solution.py
409	Longest Palindrome	Easy	solution.py
416	Partition Equal Subset Sum	Medium	solution.py
438	Find All Anagrams in a String	Medium	solution.py
542	01 Matrix	Medium	solution.py
543	Diameter of Binary Tree	Easy	solution.py
621	Task Scheduler	Medium	solution.py
704	Binary Search	Easy	solution.py
721	Accounts Merge	Medium	solution.py
733	Flood Fill	Easy	solution.py
876	Middle of the Linked List	Easy	solution.py
973	K Closest Points to Origin	Medium	solution.py
981	Time Based Key-Value Store	Medium	solution.py
994	Rotting Oranges	Medium	solution.py
1235	Maximum Profit in Job Scheduling	Hard	solution.py

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Grind 75 in Python with Tested Solutions