Solutions for Leetcode problems

Problem	Solutions
0001_Two_Sum	one_hash.py brute_force.java
0002_Add_Two_Numbers	trival.java
0003_Longest_Substring_Without_Repeating_Characters prob.md	hashmap_one_pass.java ⭐️ hashmap_and_two_points.py
0004_Median_of_Two_Sorted_Arrays prob.md	binary_search.java ⭐️
0005_Longest_Palindromic_Substring	dp_linear_space.py trick_expand_center.java ⭐️
0006_ZigZag_Conversion	trival.java
0007_Reverse_Integer	trival_overflow_checking.java
0008_String_to_Integer_atoi	trival.java
0009_Palindrome_Number	overflow_check.java
0010_Regular_Expression_Matching	dp.java
0011_Container_With_Most_Water	trick_greedy.java
0012_Integer_to_Roman	trival.java
0013_Roman_to_Integer	trival.java
0014_Longest_Common_Prefix	divide_conquer.py trie.py trival.java
0015_3Sum	shrink_both_side.py
0016_3Sum_Closest	shrink_both_side.py
0017_Letter_Combinations_of_a_Phone_Number	backtracking.java list_expanding.py ⭐️ backtracking.py
0018_4Sum	def_2sum_as_method.py k_sum_generized_and_hashset.java
0019_Remove_Nth_Node_From_End_of_List	trival.java
0020_Valid_Parentheses	stack.py
0021_Merge_Two_Sorted_Lists	trival_recur.py
0022_Generate_Parentheses	backtracking.java backtracking.py
0023_Merge_K_Sorted_Lists	priority_queue.java divide_conquer.py
0030_Substring_with_Concatenation_of_All_Words	sliding_window.py
0031_Next_Permutation	iter.java trival.py
0032_Longest_Valid_Parentheses	dp.java stack_two_pass.py
0033_Search_in_Rotated_Sorted_Array	binary_search.py binary_search_recur.py
0034_Find_First_and_Last_Position_of_Element_in_Sorted_Array	binary_search.py
0035_Search_Insert_Position	binary_search.py
0036_Valid_Sudoku	hashset.py
0037_Sudoku_Solver	dfs.py
0038_Count_and_Say	counting.java trival_counting.py
0039_Combination_Sum	backtracking.py
0040_Combination_Sum_II	backtracking.py
0041_First_Missing_Positive	trick_in_slot_check.py
0042_Trapping_Rain_Water	brute.py dp.py stack.py trick_two_pointers.py ⭐️
0043_Multiply_Strings	trival_reversed_list.py
0044_Wildcard_Matching	dp.py
0045_Jump_Game_II	greedy.py
0046_Permutations	list_concat.py dfs_modify_input_array.py
0047_Permutations_II	dfs.kt list_concat_pythonic.py list_concat.py list_concat.java
0048_Rotate_Image	iter_by_layer_in_space.py
0049_Group_Anagrams	concise_tuple_sorted.py
0050_Pow_x_n	recur.py iter_with_bit_opts.py ⭐️ recur.java
0051_N_Queens	backtracking.py
0052_N_Queens_II	backtracking.py
0053_Maximum_Subarray	dp.py divide_conquer.py trival.py
0054_Spiral_Matrix	check_table.py iter_by_layer.java
0055_Jump_Game	dp.py greedy.java
0056_Merge_Intervals	sort_and_iter.py sort_and_iter_comparator.java
0057_Insert_Interval	sort_and_iter.py
0058_Length_of_Last_Word	trival_fast.java trival.py
0059_Spiral_Matrix_II	iter_by_layer.py
0060_Permutation_Sequence	iter_by_group.py
0061_Rotate_List	double_pointer.py
0062_Unique_Paths	math.cpp dp_1D.java dp_2D.py
0063_Unique_Paths_II	dp_2D.java
0064_Minimum_Path_Sum	dp_2D.java
0065_Valid_Number	DFA.py regex.py
0066_Plus_One	iter.java trival.py
0067_Add_Binary	trival.py
0068_Text_Justification	trival.py
0069_Sqrt_x	newton.py
0070_Climbing_Stairs	backtracking_memo.java dp.py backtracking.java
0071_Simplify_Path	stack.py
0072_Edit_Distance	dp.py
0073_Set_Matrix_Zeroes	in_space.swift in_space_faster.py trival.java
0074_Search_a_2D_Matrix	binary_search.py
0075_Sort_Colors	inc_start_index_1_loop.py both_side_1_loop.py exchange_3_loops.py
0076_Minimum_Window_Substring	sliding_window.py record_index_by_dict_of_arr.py
0077_Combinations	backtracking_with_marks.py recur_self.java recur_self.py
0078_Subsets	iter.py recur.py bit_check.py
0079_Word_Search	dfs.py
0080_Remove_Duplicates_from_Sorted_Array_II prob.md	trival_in_place_quodratic.py trick_linear_in_place.py ⭐️
0081_Search_in_Rotated_Sorted_Array_II	binary_search.py
0082_Remove_Duplicates_from_Sorted_List_II prob.md	linked_list.py
0083_Remove_Duplicates_from_Sorted_List prob.md	linked_list.py
0084_Largest_Rectangle_in_Histogram	min_segment_tree.py stack.py recur.java
0085_Maximal_Rectangle	recur_as_0084.java
0086_Partition_List	linked_list_ops.java
0087_Scramble_String	recur_with_memo_faster.java recur_with_memo.java
0088_Merge_Sorted_Array	two_points_from_end.java
0089_Gray_Code	backtracking.java
0090_Subsets_II	repeat_on_final_list_pythonic.py repeat_on_final_list.java
0091_Decode_Ways	dp.py dp.java
0092_Reverse_Linked_List_II	linked_list_recur.py linked_list_recur_v2.py
0093_Restore_IP_Addresses	backtracking.py
0094_Binary_Tree_Inorder_Traversal	iter_with_stack.py double_stacks.java
0095_Unique_Binary_Search_Trees_II	recur_with_memo.py ⭐️
0096_Unique_Binary_Search_Trees prob.md	recur_with_memo.py ⭐️
0097_Interleaving_String	dp_2d.py
0098_Validate_Binary_Search_Tree	recur.py recur_quick.java ⭐️
0099_Recover_Binary_Search_Tree	recur_linear_space.java recur_const_space.py
0100_Same_Tree	recur.py iter_bfs.java iter_dfs.java
0101_Symmetric_Tree	recur.java
0102_Binary_Tree_Level_Order_Traversal	iter_bfs_each_level.py
0103_Binary_Tree_Zigzag_Level_Order_Traversal	iter_bfs_each_level.py
0104_Maximum_Depth_of_Binary_Tree	recur.py
0105_Construct_Binary_Tree_from_Preorder_and_Inorder_Traversal	recur.py recur.java
0106_Construct_Binary_Tree_from_Inorder_and_Postorder_Traversal	recur.py
0107_Binary_Tree_Level_Order_Traversal_II	iter_bfs_each_level.py
0108_Convert_Sorted_Array_to_Binary_Search_Tree	recur.py recur.java
0109_Convert_Sorted_List_to_Binary_Search_Tree	recur_linear.java ⭐️ recur_two_points.py
0110_Balanced_Binary_Tree	recur.py
0111_Minimum_Depth_of_Binary_Tree	recur.py iter_with_priority_queue.java iter_bfs.swift
0112_Path_Sum	recur.py
0113_Path_Sum_II	recur.py
0114_Flatten_Binary_Tree_to_Linked_List	recur_with_stack.py
0115_Distinct_Subsequences	dp_2d.py dp_1d.py
0116_Populating_Next_Right_Pointers_in_Each_Node prob.md	iter_by_level.py recur_1_param.py recur_2_params.py ⭐️
0117_Populating_Next_Right_Pointers_in_Each_Node_II prob.md	recur_bfs.py ⭐️
0118_Pascals_Triangle	iter.py
0119_Pascals_Triangle_II	iter_1d_space.py recur_with_memo_2d_space.py
0120_Triangle	dp_1d_space.py
0121_Best_Time_to_Buy_and_Sell_Stock prob.md	iter_1d_space.py iter_const_space.py
0122_Best_Time_to_Buy_and_Sell_Stock_II prob.md	iter.py
0123_Best_Time_to_Buy_and_Sell_Stock_III prob.md	dp_kn.py ⭐️ dp_kn2.py dp_kn_swapped.py ⭐️
0124_Binary_Tree_Maximum_Path_Sum	dfs.py
0125_Valid_Palindrome	two_pointer.py two_pointer_compact.py pythonic.py
0126_Word_Ladder_II prob.md	bfs_by_layer.py ⭐️
0127_Word_Ladder	bfs_faster.java ⭐️ bfs_quad.java bfs_faster.py
0128_Longest_Consecutive_Sequence	disjoint_set.py
0129_Sum_Root_to_Leaf_Numbers	dfs.py
0130_Surrounded_Regions	bfs_with_memo.py
0131_Palindrome_Partitioning	dfs_with_memo.py
0132_Palindrome_Partitioning_II	dp_with_memo.py ⭐️
0133_Clone_Graph	bfs.py
0134_Gas_Station	iter.py
0135_Candy prob.md	iter_both_sides.py ⭐️
0136_Single_Number	xor.py
0137_Single_Number_II prob.md	mod3_add.py ⭐️
0138_Copy_List_with_Random_Pointer	iter.py
0139_Word_Break prob.md	dp.py
0140_Word_Break_II prob.md	dfs_with_dp.py ⭐️
0141_Linked_List_Cycle	iter_with_hash.py two_points.java
0142_Linked_List_Cycle	two_points.java
0143_Reorder_List	two_points_with_recur.py
0144_Binary_Tree_Preorder_Traversal	iter_with_stack.java iter_with_stack.py iter_with_stack2.java
0145_Binary_Tree_Postorder_Traversal	iter_with_stack.py
0146_LRU_Cache	double_linked_list_with_hash.java
0147_Insertion_Sort_List	double_loop.java
0148_Sort_List	two_points.java two_points_const_space.java
0149_Max_Points_on_a_Line	hash_slope_n2.py hash_slope_n2_gcd_fast.py
0150_Evaluate_Reverse_Polish_Notation	stack.java
0151_Reverse_Words_in_a_String	one_liner.py const_space.cpp
0152_Maximum_Product_Subarray	iter_longer_impl.java both_end.swift ⭐️ both_sides.swift ⭐️ dp_n_space.py iter_keep_min_max.cpp ⭐️
0153_Find_Minimum_in_Rotated_Sorted_Array	binary_search.java
0154_Find_Minimum_in_Rotated_Sorted_Array_II	binary_search_with_shrink.java
0155_Min_Stack	two_stacks.java
0156_Binary_Tree_Upside_Down LintCode	dfs.java
0157_Read_N_Characters_Given_Read4 LintCode	iter_keep_last.java
0158_Read_N_Characters_Given_Read4_II_Call_multiple_times LintCode	iter_keep_last.java ⭐️
0159_Longest_Substring_with_At_Most_Two_Distinct_Characters	sliding_window.java
0160_Intersection_of_Two_Linked_Lists	hash.java two_pointers.py
0161_One_Edit_Distance LintCode	iter_linear_time.java ⭐️ dp_2d.java dp_1d.java
0162_Find_Peak_Element	binary_search.cpp ⭐️ iter_linear_time_simple.java iter_linear_time.py
0163_Missing_Ranges LintCode	iter_range_check.java iter_range_check_modified.py ⭐️
0164_Maximum_Gap	radix_sort.java sort_NlogN.java
0165_Compare_Version_Numbers	iter.py
0166_Fraction_to_Recurring_Decimal	math_hash.py math.py
0167_Two_Sum_II_Input_array_is_sorted	two_sides.py
0168_Excel_Sheet_Column_Title	iter.py
0169_Majority_Element	Boyer_Moore_Voting.py
0171_Excel_Sheet_Column_Number
0172_Factorial_Trailing_Zeroes	math.java
0173_Binary_Search_Tree_Iterator	bst_one_stack_simpler.java bst_one_stack.py
0174_Dungeon_Game	simulation_with_dp.java binary_search_with_dp.java
0179_Largest_Number	custom_sort.java
0186_Reverse_Words_in_a_String_II LintCode	const_space.cpp
0187_Repeated_DNA_Sequences	sliding_window.java sliding_window_with_hash.py ⭐️
0188_Best_Time_to_Buy_and_Sell_Stock_IV	dp_kn.py ⭐️
0189_Rotate_Array	cycle_swap.java triple_reverse.py vector_ops.cpp
0190_Reverse_Bits	iter.java both_sides.cpp
0191_Number_of_1_Bits	bit_trick.java iter.cpp
0192_Word_Frequency	one_line.sh
0193_Valid_Phone_Numbers	one_line.sh
0194_Transpose_File	awk
0195_Tenth_Line	awk
0196_Delete_Duplicate_Emails	sql
0197_Rising_Temperature	sql
0198_House_Robber	dp.py
0199_Binary_Tree_Right_Side_View	dfs.py
0200_Number_of_Islands	bfs.py
0201_Bitwise_AND_of_Numbers_Range	iter_bits.py iter_bits_modified.py
0201_Happy_Number	iter.java
0203_Remove_Linked_List_Elements	iter.java
0204_Count_Primes	prime_table.java
0205_Isomorphic_Strings	iter_faster.py iter.java
0206_Reverse_Linked_List	recur.py
0207_Course_Schedule	dfs_dag_find_cycle.py
0208_Implement_Trie	simple_trie.py
0209_Minimum_Size_Subarray_Sum	binary_search.py two_pointers.kt ⭐️
0210_Course_Schedule_II prob.md	dfs_dag_topological_sort.py bfs_topological_sort.java
0211_Add_and_Search_Word	hashmap_reverse_check.kt trie_by_hashmap.py trie_based_dfs.py
0212_Word_Search_II	trie_with_dfs.py
0213_House_Robber_II	dp_two_pass.py
0214_Shortest_Palindrome	kmp.py ⭐️ brute_force_pythonic.py
0215_Kth_Largest_Element_in_an_Array	quick_select.py priority_queue.java
0216_Combination_Sum_III	backtracking.py
0217_Contains_Duplicate	set.java
0218_The_Skyline_Problem	priority_queue_NLogN.java coordinate_compression.java
0219_Contains_Duplicate_II	hash.py
0220_Contains_Duplicate_III	treeset.java ⭐️
0221_Maximal_Square	dp_2d.py
0222_Count_Complete_Tree_Nodes	binary_search.py brute_force.java
0223_Rectangle_Area	math.py
0224_Basic_Calculator	stack.py
0225_Implement_Stack_using_Queues	two_queues.py one_queue.py
0226_Invert_Binary_Tree	recur.py
0227_Basic_Calculator_II	simu_with_stack.py
0228_Summary_Ranges	iter.java iter_with_exp_inc.java ⭐️
0229_Majority_Element_II	boyer_moore.py
0230_Kth_Smallest_Element_in_a_BST	iter_with_stack.py ⭐️ dfs.py
0231_Power_of_Two	math.py
0232_Implement_Queue_using_Stacks	double_stacks.py
0233_Number_of_Digit_One	math.py
0234_Palindrome_Linked_List	iter.py
0235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree	dfs_use_BST_property.py dfs.py
0236_Lowest_Common_Ancestor_of_a_Binary_Tree	dfs.py
0237_Delete_Node_in_a_Linked_List	swap_value.py one_swap.py
0238_Product_of_Array_Except_Self	iter_const_space.py
0239_Sliding_Window_Maximum	deque.py ⭐️
0240_Search_a_2D_Matrix_II	binary_search.java iter.java ⭐️
0241_Different_Ways_to_Add_Parentheses	divide_conquer.py ⭐️ pythonic.py
0242_Valid_Anagram	dict.py
0243_Shortest_Word_Distance LintCode	iter.py
0244_Shortest_Word_Distance_II LintCode	hash_and_merge.py
0245_Shortest_Word_Distance_III LintCode	iter.py
0246_Strobogrammatic_Number LintCode	iter.py
0247_Strobogrammatic_Number_II LintCode	iter.py ⭐️ iter.java
0248_Strobogrammatic_Number_III LintCode	iter.py ⭐️
0249_Group_Shifted_String LintCode	iter_cal_hash.py iter_cal_diff.py
0250_Count_Univalue_Subtrees LintCode	recur.py ⭐️
0251_Flatten_2D_Vector LintCode	simu.py
0252_Meeting_Rooms LintCode	sort_and_iter.java
0253_Meeting_Rooms_II LintCode	sort_and_min_q.java ⭐️ sort_and_iter_quadric.java
0254_Factor_Combinations LintCode	dfs_faster_gen_factors.py dfs.py
0255_Verify_Preorder_Sequence_in_Binary_Search_Tree prob.md LintCode	const_space.py ⭐️ stack.py ⭐️ recur_quadric.py
0256_Paint_House	dp.py
0257_Binary_Tree_Paths LintCode	recur.py
0258_Add_Digits	iter.py math.py
0259_3Sum_Smaller LintCode	iter_shrink_both_sides.java iter_shrink_both_sides_modified.py ⭐️
0260_Single_Number_III	bit_opt.py
0261_Graph_Valid_Tree LintCode	disjoint_set.py dfs.py
0263_Ugly_Number	iter.py
0264_Ugly_Number_II	math.py ⭐️
0265_Paint_House_II LintCode	dp_with_second_min.py dp_with_special_min.py
0266_Palindrome_Permutation LintCode	iter.py
0267_Palindrome_Permutation_II	unique_permutation.py
0268_Missing_Number	math_xor.py
0269_Alien_Dictionary prob.md LintCode	topological_sort.py ⭐️
0274_H_index	hash.py
0275_H-Index_II	binary_search.py
0276_Paint_Fence	math.py
0277_Find_the_Celebrity	greedy.py
0278_First_Bad_Version	binary_search.py
0279_Perfect_Squares	static_dp.py
0280_Wiggle_Sort LintCode	swap.py only_swap_N.cpp sort_and_swap_NLogN.java
0281_Zigzag_Iterator LintCode	double_index.java
0282_Expression_Add_Operators	dfs.py
0283_Move_Zeroes	iter.py
0284_Peeking_Iterator	simple.py
0285_Inorder_Successor_in_BST LintCode	binary_search.py
0286_Walls_and_Gates LintCode	bfs.py
0287_Find_the_Duplicate_Number	Floyds_Tortoise_and_Hare.py ⭐️
0288_Unique_Word_Abbreviation prob.md LintCode	set.py
0289_Game_of_Life	simu.java
0290_Word_Pattern	one_dict.py dict.py
0291_Word_Pattern_II LintCode	two_dict_and_dfs.py one_dict_and_dfs.py
0292_Nim_Game	dp.py math.py
0293_Flip_Game LintCode	simple.py
0294_Flip_Game_II LintCode	dfs_with_memo.py
0297_Serialize_and_Deserialize_Binary_Tree prob.md	bfs.py ⭐️
0299_Bulls_and_Cows	iter.py
0300_Longest_Increasing_Subsequence	dp_and_binary_search.py dp.py dp_bisect.py
0303_Range_Sum_Query_Immutable	simple.py
0304_Range_Sum_Query_2D_Immutable	2d_addup.py
0305_Number_of_Islands_II prob.md	disjoint_set.py
0306_Additive_Number	dfs.py
0307_Range_Sum_Query_Mutable	binary_indexed_tree.py ⭐️ segment_tree.py ⭐️
0308_Range_Sum_Query_2D prob.md	segment_tree.py ⭐️
0309_Best_Time_to_Buy_and_Sell_Stock_with_Cooldown	state_machine.py dp_quadric.py
0310_Minimum_Height_Trees	graph_degree.java ⭐️
0313_Super_Ugly_Number	math.py math.java
0318_Maximum_Product_of_Word_Lengths	bit_operations.py bit_operations.java
0319_Bulb_Switcher	math.java prime_table.java
0322_Coin_Change	dp_loop_index.java dp.py dp.java
0323_Number_of_Connected_Components_in_an_Undirected_Graph	disjoint_set.py
0324_Wiggle_Sort_II	median_and_3way_partition.py sort_and_pick_NLogN_pythonic.py ⭐️ sort_and_module.py sort_and_pick_NLogN.py
0325_Maximum_Size_Subarray_Sum_Equals_k	iter_and_hashmap.java
0326_Power_of_Three	iter.java
0327_Count_of_Rnage_Sum prob.md	binary_indexed_tree.py ⭐️
0328_Odd_Even_Linked_List	linked_list_opt.java
0331_Verify_Preorder_Serialization_of_a_Binary_Tree prob.md	iter_by_degrees.py stack.py
0332_Reconstruct_Itinerary	dfs2.java dfs.java
0334_Increasing_Triplet_Subsequence	iter.java
0337_House_Robber_III	dfs.java
0338_Counting_Bits	math.py math.java
0342_Power_of_Four	math.java
0343_Integer_Break	dp.java math.py
0344_Reverse_String	iter.java
0345_Reverse_Vowels_of_a_String	iter.java
0347_Top_K_Frequent_Elements	kth_partition.py hash_and_heap.java
0349_Intersection_of_Two_Arrays	hashmap.java two_sets.java
0350_Intersection_of_Two_Arrays_II	hashmap.java
0351_Android_Unlock_Patterns prob.md LintCode	dfs.java
0360_Sort_Transformed_Array prob.md	math.py two_points.java
0370_Range_Addition LintCode	iter_reduce.py
0377_Combination_Sum_IV	dp.java
0383_Ransom_Note prob.md	hashmap.py
0384_Shuffle_an_Array prob.md	iter_with_random.py
0385_Mini_Parser prob.md	recur.py
0386_Lexicographical_Numbers prob.md	recur.py
0387_First_Unique_Character_in_a_String prob.md	hashmap.py
0388_Longest_Absolute_File_Path prob.md	stack.py
0389_Find_the_Difference	xor.py hashmap.py
0390_Elimination_Game	modified_binary_search.java
0391_Perfect_Rectangle	math.py
0392_Is_Subsequence	two_pointers.py
0393_UTF-8_Validation	iter_with_bit_opts.py iter_with_bit_opts2.py
0394_Decode_String	recur.py
0395_Longest_Substring_with_At_Least_K_Repeating_Characters	sliding_window.py ⭐️ divide_conquer.py
0396_Rotate_Function	arr_sum_trick.py
0397_Integer_Replacement	bfs.py math.py
0398_Random_Pick_Index	hash.py reservoir_sampling.py
0399_Evaluate_Division	bfs.py dfs.py
0400_Nth_Digit	iter.py
0401_Binary_Watch	combinations.py
0402_Remove_K_Digits	stack.py
0403_Frog_Jump	backtracking.py
0404_Sum_of_Left_Leaves	recur.py
0405_Convert_a_Number_to_Hexadecimal	iter.py
0406_Queue_Reconstruction_by_Height	sort_and_insert.kt sort_and_insert.py ⭐️
0407_Trapping_Rain_Water_II	priority_queue.java priority_queue.py
0409_Longest_Palindrome	hash.py
0410_Split_Array_Largest_Sum	binary_search.py
0411_Minimum_Unique_Word_Abbreviation prob.md	dfs.py ⭐️
0465_Optimal_Account_Balancing prob.md LintCode	dp_by_subsets.java ⭐️ backtracking.py
0475_Heaters	two_pointers.py brute_force.java
0485_Max_Consecutive_Ones	iter.py
0487_Max_Consecutive_Ones_II	iter.py
0494_Target_Sum	recur_with_memo.py recur_brute_force.cpp dp.java
0498_Diagonal_Traverse	iter.kt iter_with_zip.py
0500_Keyboard_Row	bits_opts.py
0542_01_Matrix prob.md	bfs.py
0543_Diameter_of_Binary_Tree	dfs.py
0572_Subtree_of_Another_Tree	binary_tree_opts.py
0598_Range_Addition_II	iter.py
0673_Number_of_Longest_Increasing_Subsequence	double_dp.java ⭐️ segment_tree.py
0703_Kth_Largest_Element_in_a_Stream	heap.py priority_queue.java priority_queue.py
1263_Minimum_Moves_to_Move_a_Box_to_Their_Target_Location prob.md	double_A_star.py ⭐️
1288_Remove_Covered_Intervals	line_sweep.java
1647_Minimum_Deletions_to_Make_Character_Frequencies_Unique prob.md	iter_and_count.py