docs: add detailed problem documentation by difficulty

README.md

@@ -1 +1,60 @@
-# leetcode
+# LeetCode Python Solutions
+
+A collection of LeetCode problem solutions implemented in Python with detailed complexity analysis and test coverage.
+
+## Features
+
+- **Python Solutions**: All solutions written in Python 3
+- **Testing**: pytest test coverage for all solutions
+- **Complexity Analysis**: Detailed time and space complexity documentation for each solution
+- **Organized Structure**: Problems organized by difficulty level (Easy, Medium, Hard)
+
+## Migration Status
+
+🔄 **Currently migrating from old structure to new directory structure**
+
+This project is being reorganized. The following problems have been migrated to the new structure:
+
+- ✅ Migrated problems in `problems/` directory (83 problems listed below)
+- ⏳ Legacy problems still being migrated
+
+## Project Structure
+
+```
+leetcode/
+├── problems/
+│   ├── easy/       # Easy difficulty problems
+│   ├── medium/     # Medium difficulty problems
+│   └── hard/       # Hard difficulty problems
+├── docs/           # Detailed problem lists by difficulty
+├── tests/          # Test utilities and fixtures
+└── utils/          # Shared utilities and helpers
+```
+
+Each problem follows this structure:
+```
+{difficulty}/{problem-name}_{number}/
+├── solution.py         # Solution implementation
+├── test_solution.py    # Test cases
+└── __init__.py         # Package initialization
+```
+
+## Solutions
+
+📊 **Statistics**: 83 problems solved (migrated to new structure)
+
+| Difficulty | Count |
+|------------|-------|
+| Easy       | 58    |
+| Medium     | 24    |
+| Hard       | 1     |
+
+### Browse by Difficulty
+
+- 📗 [Easy Problems](docs/EASY.md)
+- 📘 [Medium Problems](docs/MEDIUM.md)
+- 📕 [Hard Problems](docs/HARD.md)
+
+## Author
+
+[Peter Chen](https://github.com/kobukuro)

docs/EASY.md

@@ -0,0 +1,70 @@
+# Easy Problems
+
+Total: 58 problems solved
+
+## Solutions
+
+| # | Title | Solution | Tests |
+|---|-------|----------|-------|
+| 1 | [Two Sum](https://leetcode.com/problems/two-sum/) | [solution.py](../problems/easy/two_sum_1/solution.py) | [test_solution.py](../problems/easy/two_sum_1/test_solution.py) |
+| 20 | [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/) | [solution.py](../problems/easy/valid_parentheses_20/solution.py) | [test_solution.py](../problems/easy/valid_parentheses_20/test_solution.py) |
+| 21 | [Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/) | [solution.py](../problems/easy/merge_two_sorted_lists_21/solution.py) | [test_solution.py](../problems/easy/merge_two_sorted_lists_21/test_solution.py) |
+| 26 | [Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/) | [solution.py](../problems/easy/remove_duplicates_from_sorted_array_26/solution.py) | [test_solution.py](../problems/easy/remove_duplicates_from_sorted_array_26/test_solution.py) |
+| 58 | [Length of Last Word](https://leetcode.com/problems/length-of-last-word/) | [solution.py](../problems/easy/length_of_last_word_58/solution.py) | [test_solution.py](../problems/easy/length_of_last_word_58/test_solution.py) |
+| 70 | [Climbing Stairs](https://leetcode.com/problems/climbing-stairs/) | [solution.py](../problems/easy/climbing_stairs_70/solution.py) | [test_solution.py](../problems/easy/climbing_stairs_70/test_solution.py) |
+| 88 | [Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array/) | [solution.py](../problems/easy/merge_sorted_array_88/solution.py) | [test_solution.py](../problems/easy/merge_sorted_array_88/test_solution.py) |
+| 100 | [Same Tree](https://leetcode.com/problems/same-tree/) | [solution.py](../problems/easy/same_tree_100/solution.py) | [test_solution.py](../problems/easy/same_tree_100/test_solution.py) |
+| 104 | [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/) | [solution.py](../problems/easy/maximum_depth_of_binary_tree_104/solution.py) | [test_solution.py](../problems/easy/maximum_depth_of_binary_tree_104/test_solution.py) |
+| 112 | [Path Sum](https://leetcode.com/problems/path-sum/) | [solution.py](../problems/easy/path_sum_112/solution.py) | [test_solution.py](../problems/easy/path_sum_112/test_solution.py) |
+| 141 | [Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/) | [solution.py](../problems/easy/linked_list_cycle_141/solution.py) | [test_solution.py](../problems/easy/linked_list_cycle_141/test_solution.py) |
+| 191 | [Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/) | [solution.py](../problems/easy/number_of_1_bits_191/solution.py) | [test_solution.py](../problems/easy/number_of_1_bits_191/test_solution.py) |
+| 206 | [Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/) | [solution.py](../problems/easy/reverse_linked_list_206/solution.py) | [test_solution.py](../problems/easy/reverse_linked_list_206/test_solution.py) |
+| 217 | [Contains Duplicate](https://leetcode.com/problems/contains-duplicate/) | [solution.py](../problems/easy/contains_duplicate_217/solution.py) | [test_solution.py](../problems/easy/contains_duplicate_217/test_solution.py) |
+| 226 | [Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/) | [solution.py](../problems/easy/invert_binary_tree_226/solution.py) | [test_solution.py](../problems/easy/invert_binary_tree_226/test_solution.py) |
+| 242 | [Valid Anagram](https://leetcode.com/problems/valid-anagram/) | [solution.py](../problems/easy/valid_anagram_242/solution.py) | [test_solution.py](../problems/easy/valid_anagram_242/test_solution.py) |
+| 344 | [Reverse String](https://leetcode.com/problems/reverse-string/) | [solution.py](../problems/easy/reverse_string_344/solution.py) | [test_solution.py](../problems/easy/reverse_string_344/test_solution.py) |
+| 345 | [Reverse Vowels of a String](https://leetcode.com/problems/reverse-vowels-of-a-string/) | [solution.py](../problems/easy/reverse_vowels_of_a_string_345/solution.py) | [test_solution.py](../problems/easy/reverse_vowels_of_a_string_345/test_solution.py) |
+| 383 | [Ransom Note](https://leetcode.com/problems/ransom-note/) | [solution.py](../problems/easy/ransom_note_383/solution.py) | [test_solution.py](../problems/easy/ransom_note_383/test_solution.py) |
+| 387 | [First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string/) | [solution.py](../problems/easy/first_unique_character_in_a_string_387/solution.py) | [test_solution.py](../problems/easy/first_unique_character_in_a_string_387/test_solution.py) |
+| 412 | [Fizz Buzz](https://leetcode.com/problems/fizz-buzz/) | [solution.py](../problems/easy/fizz_buzz_412/solution.py) | [test_solution.py](../problems/easy/fizz_buzz_412/test_solution.py) |
+| 509 | [Fibonacci Number](https://leetcode.com/problems/fibonacci-number/) | [solution.py](../problems/easy/fibonacci_number_509/solution.py) | [test_solution.py](../problems/easy/fibonacci_number_509/test_solution.py) |
+| 557 | [Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii/) | [solution.py](../problems/easy/reverse_words_in_a_string_III_557/solution.py) | [test_solution.py](../problems/easy/reverse_words_in_a_string_III_557/test_solution.py) |
+| 572 | [Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree/) | [solution.py](../problems/easy/subtree_of_another_tree_572/solution.py) | [test_solution.py](../problems/easy/subtree_of_another_tree_572/test_solution.py) |
+| 700 | [Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/) | [solution.py](../problems/easy/search_in_a_binary_search_tree_700/solution.py) | [test_solution.py](../problems/easy/search_in_a_binary_search_tree_700/test_solution.py) |
+| 704 | [Binary Search](https://leetcode.com/problems/binary-search/) | [solution.py](../problems/easy/binary_search_704/solution.py) | [test_solution.py](../problems/easy/binary_search_704/test_solution.py) |
+| 709 | [To Lower Case](https://leetcode.com/problems/to-lower-case/) | [solution.py](../problems/easy/to_lower_case_709/solution.py) | [test_solution.py](../problems/easy/to_lower_case_709/test_solution.py) |
+| 771 | [Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/) | [solution.py](../problems/easy/jewels_and_stones_771/solution.py) | [test_solution.py](../problems/easy/jewels_and_stones_771/test_solution.py) |
+| 804 | [Unique Morse Code Words](https://leetcode.com/problems/unique-morse-code-words/) | [solution.py](../problems/easy/unique_morse_code_words_804/solution.py) | [test_solution.py](../problems/easy/unique_morse_code_words_804/test_solution.py) |
+| 977 | [Squares of a Sorted Array](https://leetcode.com/problems/squares-of-a-sorted-array/) | [solution.py](../problems/easy/squares_of_a_sorted_array_977/solution.py) | [test_solution.py](../problems/easy/squares_of_a_sorted_array_977/test_solution.py) |
+| 1119 | [Remove Vowels from a String](https://leetcode.com/problems/remove-vowels-from-a-string/) | [solution.py](../problems/easy/remove_vowels_from_a_string_1119/solution.py) | [test_solution.py](../problems/easy/remove_vowels_from_a_string_1119/test_solution.py) |
+| 1160 | [Find Words That Can Be Formed by Characters](https://leetcode.com/problems/find-words-that-can-be-formed-by-characters/) | [solution.py](../problems/easy/find_words_that_can_be_formed_by_characters_1160/solution.py) | [test_solution.py](../problems/easy/find_words_that_can_be_formed_by_characters_1160/test_solution.py) |
+| 1323 | [Maximum 69 Number](https://leetcode.com/problems/maximum-69-number/) | [solution.py](../problems/easy/maximum_69_number_1323/solution.py) | [test_solution.py](../problems/easy/maximum_69_number_1323/test_solution.py) |
+| 1365 | [How Many Numbers Are Smaller Than the Current Number](https://leetcode.com/problems/how-many-numbers-are-smaller-than-the-current-number/) | [solution.py](../problems/easy/how_many_numbers_are_smaller_than_the_current_number_1365/solution.py) | [test_solution.py](../problems/easy/how_many_numbers_are_smaller_than_the_current_number_1365/test_solution.py) |
+| 1389 | [Create Target Array in the Given Order](https://leetcode.com/problems/create-target-array-in-the-given-order/) | [solution.py](../problems/easy/create_target_array_in_the_given_order_1389/solution.py) | [test_solution.py](../problems/easy/create_target_array_in_the_given_order_1389/test_solution.py) |
+| 1431 | [Kids With the Greatest Number of Candies](https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/) | [solution.py](../problems/easy/kids_with_the_greatest_number_of_candies_1431/solution.py) | [test_solution.py](../problems/easy/kids_with_the_greatest_number_of_candies_1431/test_solution.py) |
+| 1436 | [Destination City](https://leetcode.com/problems/destination-city/) | [solution.py](../problems/easy/destination_city_1436/solution.py) | [test_solution.py](../problems/easy/destination_city_1436/test_solution.py) |
+| 1603 | [Design Parking System](https://leetcode.com/problems/design-parking-system/) | [solution.py](../problems/easy/design_parking_system_1603/solution.py) | [test_solution.py](../problems/easy/design_parking_system_1603/test_solution.py) |
+| 1662 | [Check If Two String Arrays Are Equivalent](https://leetcode.com/problems/check-if-two-string-arrays-are-equivalent/) | [solution.py](../problems/easy/check_if_two_string_arrays_are_equivalent_1662/solution.py) | [test_solution.py](../problems/easy/check_if_two_string_arrays_are_equivalent_1662/test_solution.py) |
+| 1672 | [Richest Customer Wealth](https://leetcode.com/problems/richest-customer-wealth/) | [solution.py](../problems/easy/richest_customer_wealth_1672/solution.py) | [test_solution.py](../problems/easy/richest_customer_wealth_1672/test_solution.py) |
+| 1773 | [Count Items Matching a Rule](https://leetcode.com/problems/count-items-matching-a-rule/) | [solution.py](../problems/easy/count_items_matching_a_rule_1773/solution.py) | [test_solution.py](../problems/easy/count_items_matching_a_rule_1773/test_solution.py) |
+| 1816 | [Truncate Sentence](https://leetcode.com/problems/truncate-sentence/) | [solution.py](../problems/easy/truncate_sentence_1816/solution.py) | [test_solution.py](../problems/easy/truncate_sentence_1816/test_solution.py) |
+| 1929 | [Concatenation of Array](https://leetcode.com/problems/concatenation-of-array/) | [solution.py](../problems/easy/concatenation_of_array_1929/solution.py) | [test_solution.py](../problems/easy/concatenation_of_array_1929/test_solution.py) |
+| 1941 | [Check if All Characters Have Equal Number of Occurrences](https://leetcode.com/problems/check-if-all-characters-have-equal-number-of-occurrences/) | [solution.py](../problems/easy/CheckIfAllCharactersHaveEqualNumberOfOccurrences1941/solution.py) | [test_solution.py](../problems/easy/CheckIfAllCharactersHaveEqualNumberOfOccurrences1941/test_solution.py) |
+| 2011 | [Final Value of Variable After Performing Operations](https://leetcode.com/problems/final-value-of-variable-after-performing-operations/) | [solution.py](../problems/easy/final_value_of_variable_after_performing_operations_2011/solution.py) | [test_solution.py](../problems/easy/final_value_of_variable_after_performing_operations_2011/test_solution.py) |
+| 2057 | [Smallest Index With Equal Value](https://leetcode.com/problems/smallest-index-with-equal-value/) | [solution.py](../problems/easy/smallest_index_with_equal_value_2057/solution.py) | [test_solution.py](../problems/easy/smallest_index_with_equal_value_2057/test_solution.py) |
+| 2114 | [Maximum Number of Words Found in Sentences](https://leetcode.com/problems/maximum-number-of-words-found-in-sentences/) | [solution.py](../problems/easy/maximum_number_of_words_found_in_sentences_2114/solution.py) | [test_solution.py](../problems/easy/maximum_number_of_words_found_in_sentences_2114/test_solution.py) |
+| 2124 | [Check if All A's Appears Before All B's](https://leetcode.com/problems/check-if-all-as-appears-before-all-bs/) | [solution.py](../problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/solution.py) | [test_solution.py](../problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/test_solution.py) |
+| 2129 | [Capitalize the Title](https://leetcode.com/problems/capitalize-the-title/) | [solution.py](../problems/easy/capitalize_the_title_2129/solution.py) | [test_solution.py](../problems/easy/capitalize_the_title_2129/test_solution.py) |
+| 2185 | [Counting Words With a Given Prefix](https://leetcode.com/problems/counting-words-with-a-given-prefix/) | [solution.py](../problems/easy/counting_words_with_a_given_prefix_2185/solution.py) | [test_solution.py](../problems/easy/counting_words_with_a_given_prefix_2185/test_solution.py) |
+| 2215 | [Find the Difference of Two Arrays](https://leetcode.com/problems/find-the-difference-of-two-arrays/) | [solution.py](../problems/easy/find_the_difference_of_two_arrays_2215/solution.py) | [test_solution.py](../problems/easy/find_the_difference_of_two_arrays_2215/test_solution.py) |
+| 2315 | [Count Asterisks](https://leetcode.com/problems/count-asterisks/) | [solution.py](../problems/easy/count_asterisks_2315/solution.py) | [test_solution.py](../problems/easy/count_asterisks_2315/test_solution.py) |
+| 2469 | [Convert the Temperature](https://leetcode.com/problems/convert-the-temperature/) | [solution.py](../problems/easy/convert_the_temperature_2469/solution.py) | [test_solution.py](../problems/easy/convert_the_temperature_2469/test_solution.py) |
+| 2710 | [Remove Trailing Zeros From a String](https://leetcode.com/problems/remove-trailing-zeros-from-a-string/) | [solution.py](../problems/easy/remove_trailing_zeros_from_a_string_2710/solution.py) | [test_solution.py](../problems/easy/remove_trailing_zeros_from_a_string_2710/test_solution.py) |
+| 2798 | [Number of Employees Who Met the Target](https://leetcode.com/problems/number-of-employees-who-met-the-target/) | [solution.py](../problems/easy/number_of_employees_who_met_the_target_2798/solution.py) | [test_solution.py](../problems/easy/number_of_employees_who_met_the_target_2798/test_solution.py) |
+| 2942 | [Find Words Containing Character](https://leetcode.com/problems/find-words-containing-character/) | [solution.py](../problems/easy/find_words_containing_character_2942/solution.py) | [test_solution.py](../problems/easy/find_words_containing_character_2942/test_solution.py) |
+| 3110 | [Score of a String](https://leetcode.com/problems/score-of-a-string/) | [solution.py](../problems/easy/score_of_a_string_3110/solution.py) | [test_solution.py](../problems/easy/score_of_a_string_3110/test_solution.py) |
+| 3289 | [The Two Sneaky Numbers of Digitville](https://leetcode.com/problems/the-two-sneaky-numbers-of-digitville/) | [solution.py](../problems/easy/the_two_sneaky_numbers_of_digitville_3289/solution.py) | [test_solution.py](../problems/easy/the_two_sneaky_numbers_of_digitville_3289/test_solution.py) |
+
+---
+
+[← Back to Main README](../README.md)

docs/HARD.md

@@ -0,0 +1,13 @@
+# Hard Problems
+
+Total: 1 problem solved
+
+## Solutions
+
+| # | Title | Solution | Tests |
+|---|-------|----------|-------|
+| 329 | [Longest Increasing Path in a Matrix](https://leetcode.com/problems/longest-increasing-path-in-a-matrix/) | [solution.py](../problems/hard/longest_increasing_path_in_a_matrix_329/solution.py) | [test_solution.py](../problems/hard/longest_increasing_path_in_a_matrix_329/test_solution.py) |
+
+---
+
+[← Back to Main README](../README.md)