NeetCode 150 Java Solutions

Topic-wise Java solutions scaffold based on the NeetCode Top 150 list from this LeetCode Discuss post: https://leetcode.com/discuss/post/5808617/heres-the-list-of-neetcodes-top-150-ques-rydm/

Each topic lives under src/main/java. Topic and problem packages are numbered in source-list order while remaining Java-valid. Each problem starts with BruteForce.java; add additional approach classes when needed.

Example:

src/main/java/t01_array_and_hashing/
  p005_maximum_subarray/
    BruteForce.java
    KadanesAlgorithm.java

Build

Run:

mvn clean package

The Maven build compiles the Java files under src/main/java. Package names are Java-valid and include order prefixes, for example t01_array_and_hashing.p005_maximum_subarray.

If Maven cannot reach the configured artifact repository, use the network-free local build:

./scripts/build.sh

Progress

Topic	Completed	Total	Progress
Array & Hashing	0	10	0%
Two Pointers	0	9	0%
Sliding Window	0	6	0%
Stack	0	9	0%
Binary Search	0	7	0%
Linked List	0	9	0%
Trees	0	10	0%
Tries	0	3	0%
Heap / Priority Queue	0	6	0%
Backtracking	0	6	0%
Graphs	0	11	0%
1-D Dynamic Programming	0	9	0%
2-D Dynamic Programming	0	8	0%
Greedy	0	10	0%
Intervals	0	5	0%
Math & Geometry	0	8	0%
Bit Manipulation	0	6	0%
Advanced Topics (Hard)	0	18	0%

Summary

Metric	Count
Topic groups	18
Listed problem entries	150

Note: the source list intentionally repeats some problems across multiple topics. This repo preserves that topic-wise segregation.

All Entries

#	Topic	Problem	Directory
1	Array & Hashing	Two Sum	t01_array_and_hashing/p001_two_sum
2	Array & Hashing	Valid Anagram	t01_array_and_hashing/p002_valid_anagram
3	Array & Hashing	Contains Duplicate	t01_array_and_hashing/p003_contains_duplicate
4	Array & Hashing	Product of Array Except Self	t01_array_and_hashing/p004_product_of_array_except_self
5	Array & Hashing	Maximum Subarray	t01_array_and_hashing/p005_maximum_subarray
6	Array & Hashing	Maximum Product Subarray	t01_array_and_hashing/p006_maximum_product_subarray
7	Array & Hashing	Find Minimum in Rotated Sorted Array	t01_array_and_hashing/p007_find_minimum_in_rotated_sorted_array
8	Array & Hashing	Search in Rotated Sorted Array	t01_array_and_hashing/p008_search_in_rotated_sorted_array
9	Array & Hashing	3Sum	t01_array_and_hashing/p009_3sum
10	Array & Hashing	Container With Most Water	t01_array_and_hashing/p010_container_with_most_water
11	Two Pointers	Valid Palindrome	t02_two_pointers/p011_valid_palindrome
12	Two Pointers	3Sum	t02_two_pointers/p012_3sum
13	Two Pointers	Container With Most Water	t02_two_pointers/p013_container_with_most_water
14	Two Pointers	Trapping Rain Water	t02_two_pointers/p014_trapping_rain_water
15	Two Pointers	Best Time to Buy and Sell Stock	t02_two_pointers/p015_best_time_to_buy_and_sell_stock
16	Two Pointers	Longest Substring Without Repeating Characters	t02_two_pointers/p016_longest_substring_without_repeating_characters
17	Two Pointers	Palindromic Substrings	t02_two_pointers/p017_palindromic_substrings
18	Two Pointers	Longest Palindromic Substring	t02_two_pointers/p018_longest_palindromic_substring
19	Two Pointers	Find Median of Two Sorted Arrays	t02_two_pointers/p019_median_of_two_sorted_arrays
20	Sliding Window	Best Time to Buy and Sell Stock	t03_sliding_window/p020_best_time_to_buy_and_sell_stock
21	Sliding Window	Longest Substring Without Repeating Characters	t03_sliding_window/p021_longest_substring_without_repeating_characters
22	Sliding Window	Longest Repeating Character Replacement	t03_sliding_window/p022_longest_repeating_character_replacement
23	Sliding Window	Permutation in String	t03_sliding_window/p023_permutation_in_string
24	Sliding Window	Minimum Window Substring	t03_sliding_window/p024_minimum_window_substring
25	Sliding Window	Sliding Window Maximum	t03_sliding_window/p025_sliding_window_maximum
26	Stack	Valid Parentheses	t04_stack/p026_valid_parentheses
27	Stack	Min Stack	t04_stack/p027_min_stack
28	Stack	Generate Parentheses	t04_stack/p028_generate_parentheses
29	Stack	Daily Temperatures	t04_stack/p029_daily_temperatures
30	Stack	Evaluate Reverse Polish Notation	t04_stack/p030_evaluate_reverse_polish_notation
31	Stack	Largest Rectangle in Histogram	t04_stack/p031_largest_rectangle_in_histogram
32	Stack	Car Fleet	t04_stack/p032_car_fleet
33	Stack	Binary Search Tree Iterator	t04_stack/p033_binary_search_tree_iterator
34	Stack	Basic Calculator II	t04_stack/p034_basic_calculator_ii
35	Binary Search	Binary Search	t05_binary_search/p035_binary_search
36	Binary Search	Search 2D Matrix	t05_binary_search/p036_search_a_2d_matrix
37	Binary Search	Koko Eating Bananas	t05_binary_search/p037_koko_eating_bananas
38	Binary Search	Find Minimum in Rotated Sorted Array	t05_binary_search/p038_find_minimum_in_rotated_sorted_array
39	Binary Search	Search in Rotated Sorted Array	t05_binary_search/p039_search_in_rotated_sorted_array
40	Binary Search	Time Based Key-Value Store	t05_binary_search/p040_time_based_key_value_store
41	Binary Search	Median of Two Sorted Arrays	t05_binary_search/p041_median_of_two_sorted_arrays
42	Linked List	Reverse Linked List	t06_linked_list/p042_reverse_linked_list
43	Linked List	Merge Two Sorted Lists	t06_linked_list/p043_merge_two_sorted_lists
44	Linked List	Reorder List	t06_linked_list/p044_reorder_list
45	Linked List	Remove Nth Node From End of List	t06_linked_list/p045_remove_nth_node_from_end_of_list
46	Linked List	Copy List With Random Pointer	t06_linked_list/p046_copy_list_with_random_pointer
47	Linked List	Add Two Numbers	t06_linked_list/p047_add_two_numbers
48	Linked List	Linked List Cycle	t06_linked_list/p048_linked_list_cycle
49	Linked List	Intersection of Two Linked Lists	t06_linked_list/p049_intersection_of_two_linked_lists
50	Linked List	LRU Cache	t06_linked_list/p050_lru_cache
51	Trees	Maximum Depth of Binary Tree	t07_trees/p051_maximum_depth_of_binary_tree
52	Trees	Same Tree	t07_trees/p052_same_tree
53	Trees	Invert Binary Tree	t07_trees/p053_invert_binary_tree
54	Trees	Binary Tree Maximum Path Sum	t07_trees/p054_binary_tree_maximum_path_sum
55	Trees	Binary Tree Level Order Traversal	t07_trees/p055_binary_tree_level_order_traversal
56	Trees	Subtree of Another Tree	t07_trees/p056_subtree_of_another_tree
57	Trees	Construct Binary Tree from Preorder and Inorder Traversal	t07_trees/p057_construct_binary_tree_from_preorder_and_inorder_traversal
58	Trees	Validate Binary Search Tree	t07_trees/p058_validate_binary_search_tree
59	Trees	Kth Smallest Element in a BST	t07_trees/p059_kth_smallest_element_in_a_bst
60	Trees	Lowest Common Ancestor of a Binary Tree	t07_trees/p060_lowest_common_ancestor_of_a_binary_tree
61	Tries	Implement Trie (Prefix Tree)	t08_tries/p061_implement_trie_prefix_tree
62	Tries	Design Add and Search Words Data Structure	t08_tries/p062_design_add_and_search_words_data_structure
63	Tries	Word Search II	t08_tries/p063_word_search_ii
64	Heap / Priority Queue	Kth Largest Element in an Array	t09_heap_priority_queue/p064_kth_largest_element_in_an_array
65	Heap / Priority Queue	Task Scheduler	t09_heap_priority_queue/p065_task_scheduler
66	Heap / Priority Queue	Design Twitter	t09_heap_priority_queue/p066_design_twitter
67	Heap / Priority Queue	Find Median from Data Stream	t09_heap_priority_queue/p067_find_median_from_data_stream
68	Heap / Priority Queue	Merge K Sorted Lists	t09_heap_priority_queue/p068_merge_k_sorted_lists
69	Heap / Priority Queue	Top K Frequent Elements	t09_heap_priority_queue/p069_top_k_frequent_elements
70	Backtracking	Subsets	t10_backtracking/p070_subsets
71	Backtracking	Combination Sum	t10_backtracking/p071_combination_sum
72	Backtracking	Permutations	t10_backtracking/p072_permutations
73	Backtracking	Word Search	t10_backtracking/p073_word_search
74	Backtracking	Palindrome Partitioning	t10_backtracking/p074_palindrome_partitioning
75	Backtracking	N-Queens	t10_backtracking/p075_n_queens
76	Graphs	Number of Islands	t11_graphs/p076_number_of_islands
77	Graphs	Clone Graph	t11_graphs/p077_clone_graph
78	Graphs	Max Area of Island	t11_graphs/p078_max_area_of_island
79	Graphs	Pacific Atlantic Water Flow	t11_graphs/p079_pacific_atlantic_water_flow
80	Graphs	Surrounded Regions	t11_graphs/p080_surrounded_regions
81	Graphs	Rotting Oranges	t11_graphs/p081_rotting_oranges
82	Graphs	Course Schedule	t11_graphs/p082_course_schedule
83	Graphs	Course Schedule II	t11_graphs/p083_course_schedule_ii
84	Graphs	Alien Dictionary	t11_graphs/p084_alien_dictionary
85	Graphs	Graph Valid Tree	t11_graphs/p085_graph_valid_tree
86	Graphs	Number of Connected Components in an Undirected Graph	t11_graphs/p086_number_of_connected_components_in_an_undirected_graph
87	1-D Dynamic Programming	Climbing Stairs	t12_1_d_dynamic_programming/p087_climbing_stairs
88	1-D Dynamic Programming	House Robber	t12_1_d_dynamic_programming/p088_house_robber
89	1-D Dynamic Programming	House Robber II	t12_1_d_dynamic_programming/p089_house_robber_ii
90	1-D Dynamic Programming	Longest Palindromic Subsequence	t12_1_d_dynamic_programming/p090_longest_palindromic_subsequence
91	1-D Dynamic Programming	Palindromic Substrings	t12_1_d_dynamic_programming/p091_palindromic_substrings
92	1-D Dynamic Programming	Decode Ways	t12_1_d_dynamic_programming/p092_decode_ways
93	1-D Dynamic Programming	Coin Change	t12_1_d_dynamic_programming/p093_coin_change
94	1-D Dynamic Programming	Longest Increasing Subsequence	t12_1_d_dynamic_programming/p094_longest_increasing_subsequence
95	1-D Dynamic Programming	Partition Equal Subset Sum	t12_1_d_dynamic_programming/p095_partition_equal_subset_sum
96	2-D Dynamic Programming	Unique Paths	t13_2_d_dynamic_programming/p096_unique_paths
97	2-D Dynamic Programming	Longest Common Subsequence	t13_2_d_dynamic_programming/p097_longest_common_subsequence
98	2-D Dynamic Programming	Word Break	t13_2_d_dynamic_programming/p098_word_break
99	2-D Dynamic Programming	Combination Sum IV	t13_2_d_dynamic_programming/p099_combination_sum_iv
100	2-D Dynamic Programming	Minimum Path Sum	t13_2_d_dynamic_programming/p100_minimum_path_sum
101	2-D Dynamic Programming	Edit Distance	t13_2_d_dynamic_programming/p101_edit_distance
102	2-D Dynamic Programming	Maximal Square	t13_2_d_dynamic_programming/p102_maximal_square
103	2-D Dynamic Programming	Burst Balloons	t13_2_d_dynamic_programming/p103_burst_balloons
104	Greedy	Maximum Subarray	t14_greedy/p104_maximum_subarray
105	Greedy	Jump Game	t14_greedy/p105_jump_game
106	Greedy	Jump Game II	t14_greedy/p106_jump_game_ii
107	Greedy	Gas Station	t14_greedy/p107_gas_station
108	Greedy	Hand of Straights	t14_greedy/p108_hand_of_straights
109	Greedy	Merge Intervals	t14_greedy/p109_merge_intervals
110	Greedy	Insert Interval	t14_greedy/p110_insert_interval
111	Greedy	Non-overlapping Intervals	t14_greedy/p111_non_overlapping_intervals
112	Greedy	Meeting Rooms	t14_greedy/p112_meeting_rooms
113	Greedy	Meeting Rooms II	t14_greedy/p113_meeting_rooms_ii
114	Intervals	Merge Intervals	t15_intervals/p114_merge_intervals
115	Intervals	Insert Interval	t15_intervals/p115_insert_interval
116	Intervals	Non-overlapping Intervals	t15_intervals/p116_non_overlapping_intervals
117	Intervals	Meeting Rooms	t15_intervals/p117_meeting_rooms
118	Intervals	Meeting Rooms II	t15_intervals/p118_meeting_rooms_ii
119	Math & Geometry	Rotate Image	t16_math_and_geometry/p119_rotate_image
120	Math & Geometry	Spiral Matrix	t16_math_and_geometry/p120_spiral_matrix
121	Math & Geometry	Set Matrix Zeroes	t16_math_and_geometry/p121_set_matrix_zeroes
122	Math & Geometry	Happy Number	t16_math_and_geometry/p122_happy_number
123	Math & Geometry	Plus One	t16_math_and_geometry/p123_plus_one
124	Math & Geometry	Pow(x, n)	t16_math_and_geometry/p124_powx_n
125	Math & Geometry	Multiply Strings	t16_math_and_geometry/p125_multiply_strings
126	Math & Geometry	Rotate Array	t16_math_and_geometry/p126_rotate_array
127	Bit Manipulation	Single Number	t17_bit_manipulation/p127_single_number
128	Bit Manipulation	Number of 1 Bits	t17_bit_manipulation/p128_number_of_1_bits
129	Bit Manipulation	Counting Bits	t17_bit_manipulation/p129_counting_bits
130	Bit Manipulation	Reverse Bits	t17_bit_manipulation/p130_reverse_bits
131	Bit Manipulation	Missing Number	t17_bit_manipulation/p131_missing_number
132	Bit Manipulation	Sum of Two Integers	t17_bit_manipulation/p132_sum_of_two_integers
133	Advanced Topics (Hard)	Reverse Nodes in k-Group	t18_advanced_topics_hard/p133_reverse_nodes_in_k_group
134	Advanced Topics (Hard)	Median of Two Sorted Arrays	t18_advanced_topics_hard/p134_median_of_two_sorted_arrays
135	Advanced Topics (Hard)	Trapping Rain Water	t18_advanced_topics_hard/p135_trapping_rain_water
136	Advanced Topics (Hard)	Longest Valid Parentheses	t18_advanced_topics_hard/p136_longest_valid_parentheses
137	Advanced Topics (Hard)	Regular Expression Matching	t18_advanced_topics_hard/p137_regular_expression_matching
138	Advanced Topics (Hard)	Wildcard Matching	t18_advanced_topics_hard/p138_wildcard_matching
139	Advanced Topics (Hard)	Word Ladder	t18_advanced_topics_hard/p139_word_ladder
140	Advanced Topics (Hard)	Word Ladder II	t18_advanced_topics_hard/p140_word_ladder_ii
141	Advanced Topics (Hard)	Edit Distance	t18_advanced_topics_hard/p141_edit_distance
142	Advanced Topics (Hard)	Maximum Flow (Not on LeetCode)	t18_advanced_topics_hard/p142_maximum_flow
143	Advanced Topics (Hard)	Insert Interval	t18_advanced_topics_hard/p143_insert_interval
144	Advanced Topics (Hard)	Serialize and Deserialize Binary Tree	t18_advanced_topics_hard/p144_serialize_and_deserialize_binary_tree
145	Advanced Topics (Hard)	Alien Dictionary	t18_advanced_topics_hard/p145_alien_dictionary
146	Advanced Topics (Hard)	Palindrome Pairs	t18_advanced_topics_hard/p146_palindrome_pairs
147	Advanced Topics (Hard)	Maximal Rectangle	t18_advanced_topics_hard/p147_maximal_rectangle
148	Advanced Topics (Hard)	First Missing Positive	t18_advanced_topics_hard/p148_first_missing_positive
149	Advanced Topics (Hard)	Largest Rectangle in Histogram	t18_advanced_topics_hard/p149_largest_rectangle_in_histogram
150	Advanced Topics (Hard)	N-Queens II	t18_advanced_topics_hard/p150_n_queens_ii