Stack in Python with Tests

Stack holds 101 problems (20 Easy, 56 Medium, 25 Hard). Generate any of them into the current directory with lcpy gen -n <number>.

#	Problem	Difficulty	Solution
20	Valid Parentheses	Easy	solution.py
32	Longest Valid Parentheses	Hard	solution.py
42	Trapping Rain Water	Hard	solution.py
71	Simplify Path	Medium	solution.py
84	Largest Rectangle in Histogram	Hard	solution.py
85	Maximal Rectangle	Hard	solution.py
94	Binary Tree Inorder Traversal	Easy	solution.py
114	Flatten Binary Tree to Linked List	Medium	solution.py
143	Reorder List	Medium	solution.py
144	Binary Tree Preorder Traversal	Easy	solution.py
145	Binary Tree Postorder Traversal	Easy	solution.py
150	Evaluate Reverse Polish Notation	Medium	solution.py
155	Min Stack	Medium	solution.py
173	Binary Search Tree Iterator	Medium	solution.py
224	Basic Calculator	Hard	solution.py
225	Implement Stack using Queues	Easy	solution.py
227	Basic Calculator II	Medium	solution.py
232	Implement Queue using Stacks	Easy	solution.py
234	Palindrome Linked List	Easy	solution.py
255	Verify Preorder Sequence in Binary Search Tree	Medium	solution.py
272	Closest Binary Search Tree Value II	Hard	solution.py
316	Remove Duplicate Letters	Medium	solution.py
321	Create Maximum Number	Hard	solution.py
331	Verify Preorder Serialization of a Binary Tree	Medium	solution.py
341	Flatten Nested List Iterator	Medium	solution.py
364	Nested List Weight Sum II	Medium	solution.py
385	Mini Parser	Medium	solution.py
388	Longest Absolute File Path	Medium	solution.py
394	Decode String	Medium	solution.py
402	Remove K Digits	Medium	solution.py
426	Convert Binary Search Tree to Sorted Doubly Linked List	Medium	solution.py
439	Ternary Expression Parser	Medium	solution.py
445	Add Two Numbers II	Medium	solution.py
456	132 Pattern	Medium	solution.py
484	Find Permutation	Medium	solution.py
488	Zuma Game	Hard	solution.py
496	Next Greater Element I	Easy	solution.py
503	Next Greater Element II	Medium	solution.py
536	Construct Binary Tree from String	Medium	solution.py
581	Shortest Unsorted Continuous Subarray	Medium	solution.py
589	N-ary Tree Preorder Traversal	Easy	solution.py
590	N-ary Tree Postorder Traversal	Easy	solution.py
591	Tag Validator	Hard	solution.py
636	Exclusive Time of Functions	Medium	solution.py
654	Maximum Binary Tree	Medium	solution.py
678	Valid Parenthesis String	Medium	solution.py
682	Baseball Game	Easy	solution.py
716	Max Stack	Hard	solution.py
726	Number of Atoms	Hard	solution.py
735	Asteroid Collision	Medium	solution.py
736	Parse Lisp Expression	Hard	solution.py
739	Daily Temperatures	Medium	solution.py
768	Max Chunks To Make Sorted II	Hard	solution.py
769	Max Chunks To Make Sorted	Medium	solution.py
770	Basic Calculator IV	Hard	solution.py
772	Basic Calculator III	Hard	solution.py
844	Backspace String Compare	Easy	solution.py
853	Car Fleet	Medium	solution.py
856	Score of Parentheses	Medium	solution.py
880	Decoded String at Index	Medium	solution.py
895	Maximum Frequency Stack	Hard	solution.py
897	Increasing Order Search Tree	Easy	solution.py
901	Online Stock Span	Medium	solution.py
907	Sum of Subarray Minimums	Medium	solution.py
921	Minimum Add to Make Parentheses Valid	Medium	solution.py
936	Stamping The Sequence	Hard	solution.py
946	Validate Stack Sequences	Medium	solution.py
962	Maximum Width Ramp	Medium	solution.py
975	Odd Even Jump	Hard	solution.py
1106	Parsing A Boolean Expression	Hard	solution.py
1190	Reverse Substrings Between Each Pair of Parentheses	Medium	solution.py
1209	Remove All Adjacent Duplicates in String II	Medium	solution.py
1214	Two Sum BSTs	Medium	solution.py
1249	Minimum Remove to Make Valid Parentheses	Medium	solution.py
1265	Print Immutable Linked List in Reverse	Medium	solution.py
1472	Design Browser History	Medium	solution.py
1475	Final Prices With a Special Discount in a Shop	Easy	solution.py
1526	Minimum Number of Increments on Subarrays to Form a Target Array	Hard	solution.py
1544	Make The String Great	Easy	solution.py
1574	Shortest Subarray to be Removed to Make Array Sorted	Medium	solution.py
1598	Crawler Log Folder	Easy	solution.py
1614	Maximum Nesting Depth of the Parentheses	Easy	solution.py
1653	Minimum Deletions to Make String Balanced	Medium	solution.py
1700	Number of Students Unable to Eat Lunch	Easy	solution.py
1717	Maximum Score From Removing Substrings	Medium	solution.py
1762	Buildings With an Ocean View	Medium	solution.py
1793	Maximum Score of a Good Subarray	Hard	solution.py
1856	Maximum Subarray Min-Product	Medium	solution.py
1944	Number of Visible People in a Queue	Hard	solution.py
1963	Minimum Number of Swaps to Make the String Balanced	Medium	solution.py
1966	Binary Searchable Numbers in an Unsorted Array	Medium	solution.py
2116	Check if a Parentheses String Can Be Valid	Medium	solution.py
2130	Maximum Twin Sum of a Linked List	Medium	solution.py
2375	Construct Smallest Number From DI String	Medium	solution.py
2390	Removing Stars From a String	Medium	solution.py
2487	Remove Nodes From Linked List	Medium	solution.py
2696	Minimum String Length After Removing Substrings	Easy	solution.py
2751	Robot Collisions	Hard	solution.py
2818	Apply Operations to Maximize Score	Hard	solution.py
2940	Find Building Where Alice and Bob Can Meet	Hard	solution.py
3174	Clear Digits	Easy	solution.py

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Stack in Python with Tests