README
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0001_Two_Sum
- 思路1 利用hash的思想
0002_Add_Two_Numbers
- 思路1 直接从左往右加
0003_Longest_Substring_Without_Repeating_Characters
- 思路1 HashMap存放字符到索引的映射
0004_Median_of_Two_Sorted_Arrays
- 思路1 转化为求Kth smallest的数
0005_Longest_Palindromic_Substring
- slt
0006_ZigZag_Conversion
- 思路1 利用字符串list进行转换
0007_Reverse_Integer
- slt
0008_String_to_Integer_(atoi)
- 思路1 遍历字符串
0009_Palindrome_Number
- slt
0010_Regular_Expression_Matching
- slt
0011_Container_With_Most_Water
- 思路1 从两边到中间宽度递减算water
0012_Integer_to_Roman
- slt
0013_Roman_to_Integer
- 思路1 比后面小减当前，比后面大加当前
0014_Longest_Common_Prefix
- 思路1 对每一列，遍历所有字符串，比较那一列的字符
0015_3Sum
- 思路1 排序后遍历所有组合
0016_3Sum_Closest
- 思路1 类似3sum的思路1
0017_Letter_Combinations_of_a_Phone_Number
- slt
0018_4Sum
- slt
0019_Remove_Nth_Node_From_End_of_List
- 思路1 快慢指针
0020_Valid_Parentheses
- slt
0021_Merge_Two_Sorted_Lists
- 思路1 遍历即可
0022_Generate_Parentheses
- 思路1 DFS
0023_Merge_k_Sorted_Lists
- 思路1 不断的两两merge
0024_Swap_Nodes_in_Pairs
- Solution 1 direct swap
0025_Reverse_Nodes_in_k-Group
- 思路1 k个分别反转，迭代实现
0026_Remove_Duplicates_from_Sorted_Array
- 思路1 就地算法
0027_Remove_Element
- 思路1 类似第26题，只是判断的对象是给定的一个val
0028_Implement_strStr()
- slt
0029_Divide_Two_Integers
- Solution 1 Use subtraction
0030_Substring_with_Concatenation_of_All_Words
- 思路1
0031_Next_Permutation
- 思路1
0032 Longest Valid Parentheses
- 思路1 利用一个栈来存放左括号的下标
0033_Search_in_Rotated_Sorted_Array
- 思路1 只对有序的那一半进行二分查找
0034_Find_First_and_Last_Position_of_Element_in_Sorted_Array
- 思路1 二分查找
0035_Search_Insert_Position
- 思路1 二分查找
0036_Valid_Sudoku
- Solution 1 hash_table, 利用3个二维数组一起检查
0037_Sudoku_Solver
- 思路1 回溯法
0038_Count_and_Say
- slt
0039_Combination_Sum
- 思路1 DFS
0040_Combination_Sum_II
- 思路1 DFS
0041_First_Missing_Positive
- 思路1 把数组中的正数按数值重新放在数组中
0042_Trapping_Rain_Water
- 思路1 从左右按矮的一方往中间逼近
0043_Multiply_Strings
- 思路1 利用双重循环模拟标准的乘法
0044_Wildcard_Matching
- slt
0045_Jump_Game_II
- 思路1 贪心算法
0046_Permutations
- 思路1 dfs
0047_Permutations_II
- 思路1 dfs
0048_Rotate_Image
- 思路1 先上下翻转，在转置
0049_Group_Anagrams
- 思路1
0050_Pow(x, n)
- 思路1 二分递归
0051_N-Queens
- 思路1 回溯法
0052_N-Queens_II
- 思路1 回溯法
0053_Maximum_Subarray
- 思路1 dp
0054_Spiral_Matrix
- 思路1 直接四个方向扫描
0055_Jump_Game
- 思路1 贪心算法
0056_Merge_Intervals
- 思路1 按照start排序，再合并
0057_Insert_Interval
- 思路1 贪心算法
0058_Length_of_Last_Word
- 思路1 从右向左遍历
0059_Spiral_Matrix_II
- 思路1 同Spiral Matrix1
0060_Permutation_Sequence
- 思路1 利用数学特征
0061_Rotate_List
- 思路1
0062_Unique_Paths
- slt
0063_Unique_Paths_II
- 思路1 dp
0064_Minimum_Path_Sum
- 思路1 还是dp
0065_Valid_Number
- slt
0066_Plus_One
- Solution 1 simulation
0067_Add_Binary
- 思路1
0068_Text_Justification
- 思路1 贪心遍历words
0069_Sqrt(x)
- slt
0070_Climbing_Stairs
- slt
0071_Simplify_Path
- 思路1
0072_Edit_Distance
- 思路1 dp
0073_Set_Matrix_Zeroes
- 思路1
0074_Search_a_2D_Matrix
- 思路1
0075_Sort_Colors
- 思路1 遍历一次，遇到0放到前面，遇到2放到后面
0076_Minimum_Window_Substring
- 思路1 滑动窗口
0077_Combinations
- 思路1 dfs
0078_Subsets
- 思路1 Traceback
0079_Word_Search
- 思路1
0080_Remove_Duplicates_from_Sorted_Array_II
- 思路1
0081_Search_in_Rotated_Sorted_Array_II
- 思路1 只对有序的那一半进行二分查找
0082_Remove_Duplicates_from_Sorted_List_II
- 思路1 遍历一遍
0083_Remove_Duplicates_from_Sorted_List
- 思路1 遍历
0084_Largest_Rectangle_in_Histogram
- 思路1 暴力枚举
0085_Maximal_Rectangle
- 思路1 dp
0086_Partition_List
- 思路1 遍历分开，尾接法建两个链表，再连起来
0087_Scramble_String
- 思路1 递归
0088_Merge_Sorted_Array
- 思路1 归并排序
0090_Subsets_II
- 思路1 回溯 dfs
0091_Decode_Ways
- Solution 1 dp
0092_Reverse_Linked_List_II
- 思路1 反转链表，再拼接
0093_Restore_IP_Addresses
- 思路1 暴力枚举
0094_Binary_Tree_Inorder_Traversal
- slt
0095_Unique_Binary_Search_Trees_II
- 思路1 递归建树
0096_Unique_Binary_Search_Trees
- 思路1 dp
0097_Interleaving_String
- 思路1 dp
0098_Validate_Binary_Search_Tree
- 思路1 BST中序遍历结果递增
0099_Recover_Binary_Search_Tree
- 思路1 中序遍历记录错误节点
0100_Same_Tree
- 思路1 递归检查
0101_Symmetric_Tree
- 思路1 递归
0102_Binary_Tree_Level_Order_Traversal
- 思路1 利用栈
0103_Binary_Tree_Zigzag_Level_Order_Traversal
- 思路1
0104_Maximum_Depth_of_Binary_Tree
- 思路1 dfs
0105_Construct_Binary_Tree_from_Preorder_and_Inorder_Traversal
- 思路1
0106_Construct_Binary_Tree_from_Inorder_and_Postorder_Traversal
- 思路1
0107_Binary_Tree_Level_Order_Traversal_II
- 思路1
0108_Convert_Sorted_Array_to_Binary_Search_Tree
- 思路1
0109_Convert_Sorted_List_to_Binary_Search_Tree
- 思路1 用快慢指针法找到中点，再递归建树
0110_Balanced_Binary_Tree
- 思路1 递归
0111_Minimum_Depth_of_Binary_Tree
- 思路1 dfs
0112_Path_Sum
- 思路1 递归
0113_Path_Sum_II
- 思路1 dfs
0114_Flatten_Binary_Tree_to_Linked_List
- 思路1
0115_Distinct_Subsequences
- 思路1 dp
0116_Populating_Next_Right_Pointers_in_Each_Node
- 思路1 前序遍历
0117_Populating_Next_Right_Pointers_in_Each_Node_II
- 思路1 层序遍历
0118_Pascal's_Triangle
- 思路1 按数学方法添加
0119_Pascal's_Triangle_II
- slt
0120_Triangle
- 思路1 bottom-up dp
0121_Best_Time_to_Buy_and_Sell_Stock
- slt
0122_Best_Time_to_Buy_and_Sell_Stock_II
- 思路1
0123_Best_Time_to_Buy_and_Sell_Stock_III
- 思路1
0124_Binary_Tree_Maximum_Path_Sum
- 思路1 递归
0125_Valid_Palindrome
- 思路1 左右检查
0126_Word_Ladder_II
- 思路1 BFS
0127_Word_Ladder
- 思路1
0128_Longest_Consecutive_Sequence
- 思路1
0129_Sum_Root_to_Leaf_Numbers
- 思路1 dfs
0130_Surrounded_Regions
- 思路1
0132_Palindrome_Partitioning_II
- 思路1 dp
0133_Clone_Graph
- 思路1 递归dfs
0134_Gas_Station
- 思路1 一次遍历法
0135_Candy
- Solution1 greedy
0136_Single_Number
- 思路1 XOR
0137_Single_Number_II
- slt
0138_Copy_List_with_Random_Pointer
- 思路1 有丝分裂法，原地复制再分裂
0139_Word_Break
- Solution 1 dp
0141_Linked_List_Cycle
- Solution1 快慢指针
0142_Linked_List_Cycle_II
- Solution1 快慢双指针
0144_Binary_Tree_Preorder_Traversal
- 思路1 利用栈，非递归
0145_Binary_Tree_Postorder_Traversal
- Solution 1 迭代
0146_LRU_Cache
- 思路1 利用链表
0147_Insertion_Sort_List
- 思路1 插入排序
0148_Sort_List
- slt
0149_Max_Points_on_a_Line
- Solution1 暴力枚举
0150_Evaluate_Reverse_Polish_Notation
- 思路1 栈
0151_Reverse_Words_in_a_String
- 思路1
0152_Maximum_Product_Subarray
- 思路1 遍历一遍，同时记录最大和最小值
0153_Find_Minimum_in_Rotated_Sorted_Array
- 思路1 二分
0154_Find_Minimum_in_Rotated_Sorted_Array_II
- 思路1 二分
0155_Min_Stack
- 思路1
0157_Read_N_Characters_Given_Read4
- Solution1 直接循环调用
0159_Longest_Substring_with_At_Most_Two_Distinct_Characters
- 思路1 滑动窗口 + 哈希表
0160_Intersection_of_Two_Linked_Lists
- 思路1 双指针循环相遇
0162_Find_Peak_Element
- Solution 1 bisearch
0163_Missing_Ranges
- Solution1 遍历
0164_Maximum_Gap
- 思路1 桶
0165_Compare_Version_Numbers
- Solution1 遍历 + 模拟
0166_Fraction_to_Recurring_Decimal
- 思路1
0167_Two_Sum_II_-_Input_array_is_sorted
- slt
0168_Excel_Sheet_Column_Title
- 思路1 不断取余
0169_Majority_Element
- 思路1 摩尔投票法
0170_Two_Sum_III_-_Data_structure_design
- 思路1 hash 和 two sum 1 类似
0171_Excel_Sheet_Column_Number
- Solution1
0172_Factorial_Trailing_Zeroes
- 思路1 数学方法
0173_Binary_Search_Tree_Iterator
- 思路1 迭代中序遍历
0175_Combine_Two_Tables
- 思路1 直接用left join
0176_Second_Highest_Salary
- Solution 1 use max
0177_Nth_Highest_Salary
- Solution 1 Directly Single Table Query
0178_Rank_Scores
- slt
0179_Largest_Number
- 思路1 自定义排序
0180_Consecutive_Numbers
- Solution 1 三表联结
0181_Employees_Earning_More_Than_Their_Managers
- 思路1 使用 JOIN
0182_Duplicate_Emails
- 思路1 使用GROUP BY
0183_Customers_Who_Never_Order
- slt
0184_Department_Highest_Salary
- 思路1
0185_Department_Top_Three_Salaries
- Solution 1
0187_Repeated_DNA_Sequences
- Solution 1 hash map
0188_Best_Time_to_Buy_and_Sell_Stock_IV
- Solution1 DP
0189_Rotate_Array
- 思路1
0190_Reverse_Bits
- 思路1 直接把每位取出来放到一个list里，再反转构建结果
0191_Number_of_1_Bits
- 思路1 遍历数1
0196_Delete_Duplicate_Emails
- 思路1
0197_Rising_Temperature
- Solution 1 JOIN
0198_House_Robber
- 思路1 dp
0199_Binary_Tree_Right_Side_View
- 思路1
0200_Number_of_Islands
- 思路1 dfs标记岛屿
0201_Bitwise_AND_of_Numbers_Range
- 思路1
0202_Happy_Number
- 思路1 快慢
0203_Remove_Linked_List_Elements
- Solution1 遍历
0204_Count_Primes
- slt
0205_Isomorphic_Strings
- Solution1
0206_Reverse_Linked_List
- slt
0207_Course_Schedule
- 思路1 拓扑排序，队列实现
0208_Implement_Trie_(Prefix_Tree)
- 思路1
0210_Course_Schedule_II
- 思路1 topolotical sort
0211_Add_and_Search_Word_-_Data_structure_design
- Solution 1 Trie
0213_House_Robber_II
- 思路1 dp
0215_Kth_Largest_Element_in_an_Array
- 思路1 利用快排的partition
0217_Contains_Duplicate
- 思路1 hash
0218_The_Skyline_Problem
- Solution1 扫描线法
0219_Contains_Duplicate_II
- Solution1 hash
0220_Contains_Duplicate_III
- 思路1
0221_Maximal_Square
- 思路1 dp
0222_Count_Complete_Tree_Nodes
- 思路1 遍历，直接数每个结点
0223_Rectangle_Area
- 思路1
0224_Basic_Calculator
- Solution1 stack
0225_Implement_Stack_using_Queues
- 思路1 单队列实现
0226_Invert_Binary_Tree
- Solution1 dfs 后序遍历
0227_Basic_Calculator_II
- Solution1 stack
0228_Summary_Ranges
- Solution1 遍历数学模拟
0229_Majority_Element_II
- Solution 1 Boyer-Moore Algorithm
0231_Power_of_Two
- slt
0232_Implement_Queue_using_Stacks
- 思路1 两个栈来倒顺序
0233_Number_of_Digit_One
- 思路1 找规律 + 暴力
0234_Palindrome_Linked_List
- Solution 1
0235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree
- Solution1 递归检查
0236_Lowest_Common_Ancestor_of_a_Binary_Tree
- Solution 1 DFS
0237_Delete_Node_in_a_Linked_List
- Solution 1 copy value of next node
0239_Sliding_Window_Maximum
- 思路1
0240_Search_a_2D_Matrix_II
- Solution 1 Z-search
0242_Valid_Anagram
- Solution1 hash map
0243_Shortest_Word_Distance
- Solution1 遍历一次，记录索引
0244_Shortest_Word_Distance_II
- 思路1
0246_Strobogrammatic_Number
- 思路1 hash
0251_Flatten_2D_Vector
- 思路1 在初始化的时候把2D merge成1D
0252_Meeting_Rooms
- 思路1 按第一个元素排序，并判断有没有重叠
0253_Meeting_Rooms_II
- 思路1 min heap
0256_Paint_House
- 思路1 dp
0257_Binary_Tree_Paths
- Solution1 dfs
0258_Add_Digits
- Solution1 模拟
0260_Single_Number_III
- slt
0261_Graph_Valid_Tree
- 思路1 dfs
0262_Trips_and_Users
- Solution 1
0263_Ugly_Number
- Solution1 数学方法
0264_Ugly_Number_II
- 思路1 dp 三指针法
0266_Palindrome_Permutation
- Solution1 hash
0268_Missing_Number
- Solution1 数学方法
0270_Closest_Binary_Search_Tree_Value
- Solution1 二分查找
0273_Integer_to_English_Words
- Solution 1 simulation
0274_H-Index
- slt
0276_Paint_Fence
- 思路1 dp
0279_Perfect_Squares
- 思路1 dp
0283_Move_Zeroes
- slt
0289_Game_of_Life
- 思路1 用第二位存储下一阶段的状态
0290_Word_Pattern
- 思路1 hash
0293_Flip_Game
- Solution1 遍历
0295_Find_Median_from_Data_Stream
- Solution1 优先队列
0299_Bulls_and_Cows
- Solution 1 emulate + hash
0300_Longest_Increasing_Subsequence
- Solution 1 DP
0301_Remove_Invalid_Parentheses
- Solution1 DFS
0303_Range_Sum_Query_-_Immutable
- Solution1 Pre sum
0304_Range_Sum_Query_2D_-_Immutable
- Solution1 Presum
0309_Best_Time_to_Buy_and_Sell_Stock_with_Cooldown
- Solution 1 DP + state machine
0310_Minimum_Height_Trees
- 思路1 dfs 剥洋葱
0313_Super_Ugly_Number
- 思路1 DP
0318_Maximum_Product_of_Word_Lengths
- Solution 1 brute force simulation
0319_Bulb_Switcher
- Solution 1 math
0321_Create_Maximum_Number
- 思路1
0322_Coin_Change
- Solution1 dp
0323_Number_of_Connected_Components_in_an_Undirected_Graph
- 思路1 并查集
0326_Power_of_Three
- Solution1 数学方法
0328_Odd_Even_Linked_List
- 思路1 双指针
0331_Verify_Preorder_Serialization_of_a_Binary_Tree
- Solution1 计算出度和入度
0332_Reconstruct_Itinerary
- 思路1 dfs
0335_Self_Crossing
- Solution 1 by cases
0338_Counting_Bits
- Solution1
0340_Longest_Substring_with_At_Most_K_Distinct_Characters
- Solution1 sliding window + hash table
0341_Flatten_Nested_List_Iterator
- Solution1 DFS + 遞歸
0342_Power_of_Four
- Solution1 遍历
0343_Integer_Break
- slt
0344_Reverse_String
- 思路1 直接左右对换反转
0345_Reverse_Vowels_of_a_String
- Solution 1 遍历
0347_Top_K_Frequent_Elements
- 思路1 利用堆
0349_Intersection_of_Two_Arrays
- Solution 1 hash
0350_Intersection_of_Two_Arrays_II
- 思路1 hash
0352_Data_Stream_as_Disjoint_Intervals
- Solution 1 binary search + simulate
0354_Russian_Doll_Envelopes
- Solution1 DP + Sort
0355_Design_Twitter
- 思路1 记录每个tweid的时间。get的时候按时间归并
0359_Logger_Rate_Limiter
- Solution1 hash
0367_Valid_Perfect_Square
- slt
0371_Sum_of_Two_Integers
- Solution1 bit operation
0373_Find_K_Pairs_with_Smallest_Sums
- 思路1 暴力枚举所有pair，排序后，返回前k个
0375_Guess_Number_Higher_or_Lower_II
- Solution 1 DP
0376_Wiggle_Subsequence
- 思路1
0378_Kth_Smallest_Element_in_a_Sorted_Matrix
- 思路1 矩阵二分查找
0381_Insert_Delete_GetRandom_O(1)_-_Duplicates_allowed
- 思路1
0382_Linked_List_Random_Node
- Solution 1 Reservoir Sampling
0383_Ransom_Note
- Solution1 hash 表统计字符个数
0384_Shuffle_an_Array
- Solution 1 Shuffle Simulation
0387_First_Unique_Character_in_a_String
- 思路1 hash
0389_Find_the_Difference
- 思路1 hash
0391_Perfect_Rectangle
- Solution 1 geometry + hash
0392_Is_Subsequence
- 思路1
0395_Longest_Substring_with_At_Least_K_Repeating_Characters
- Solution1 Split and conquer
0397_Integer_Replacement
- Solution 1 bit + greedy
0399_Evaluate_Division
- 思路1 dfs
0401_Binary_Watch
- Solution1 遍历时间
0402_Remove_K_Digits
- 思路1
0403_Frog_Jump
- Solution1 dfs + cache
0404_Sum_of_Left_Leaves
- Solution1 dfs
0406_Queue_Reconstruction_by_Height
- Solution1 greedy
0407_Trapping_Rain_Water_II
- Solution 1 min heap
0408_Valid_Word_Abbreviation
- Solution1 遍历
0412_Fizz_Buzz
- Solution 1 traverse
0413_Arithmetic_Slices
- slt
0415_Add_Strings
- Solution 1 simulation 10-based add
0416_Partition_Equal_Subset_Sum
- Solution 1 dp
0421_Maximum_XOR_of_Two_Numbers_in_an_Array
- Solution1 位运算 + Trie
0424_Longest_Repeating_Character_Replacement
- 思路1 sliding window
0434_Number_of_Segments_in_a_String
- Solution1 遍历直接统计
0435_Non-overlapping_Intervals
- 思路1 贪心
0437_Path_Sum_III
- Solution 1 DFS
0441_Arranging_Coins
- Solution1 模拟
0443_String_Compression
- Solution1 双指针模拟
0444_Sequence_Reconstruction
- slt
0445_Add_Two_Numbers_II
- 思路1 利用stack
0446_Arithmetic_Slices_II_-_Subsequence
- Solution1 dp
0447_Number_of_Boomerangs
- slt
0448_Find_All_Numbers_Disappeared_in_an_Array
- Solution1 hash - operate on original array, mapping number to index
0450_Delete_Node_in_a_BST
- Solution 1 dfs delete
0451_Sort_Characters_By_Frequency
- 思路1 大顶堆
0452_Minimum_Number_of_Arrows_to_Burst_Balloons
- 思路1 贪心
0453_Minimum_Moves_to_Equal_Array_Elements
- Solution 1 math
0454_4Sum_II
- 思路1 hash
0455_Assign_Cookies
- Solution1 greedy
0456_132_Pattern
- Solution1 單調棧
0458_Poor_Pigs
- Solution 1 转化为 k 进制问题
0459_Repeated_Substring_Pattern
- Solution1
0460_LFU_Cache
- 思路1 hash table + 二叉平衡搜索树
0461_Hamming_Distance
- Solution1 异或
0463_Island_Perimeter
- 思路1 dfs
0474_Ones_and_Zeroes
- Solution 1 DP
0476_Number_Complement
- Solution 1 Traverse
0477_Total_Hamming_Distance
- Solution1 乘法原理
0480_Sliding_Window_Median
- 思路1 双堆 - 双堆对顶
0483_Smallest_Good_Base
- Solution1 二分 + 模拟
0485_Max_Consecutive_Ones
- Solution1 Use start to remember start of ones
0488_Zuma_Game
- Solution 1 DFS with memoization for optimization
0492_Construct_the_Rectangle
- Solution1 枚举
0493_Reverse_Pairs
- 思路1 分治。利用归并排序的思路
0494_Target_Sum
- Solution1 DFS + cache
0495_Teemo_Attacking
- Solution 1 traverse + simulate
0496_Next_Greater_Element_I
- Solution 1 Monotone Stack
0501_Find_Mode_in_Binary_Search_Tree
- Solution1 hash + dfs统计 + 遍历
0502_IPO
- Solution 1 贪心，排序 + 大顶堆
0503_Next_Greater_Element_II
- Solution1 单调栈
0504_Base_7
- Solution 1 divide and mod
0506_Relative_Ranks
- Solution 1 hash and sort
0509_Fibonacci_Number
- 思路1 递归
0511_Game_Play_Analysis_I
- Solution 1
0512_Game_Play_Analysis_II
- Solution 1
0513_Find_Bottom_Left_Tree_Value
- Solution 1 level order (dfs)
0514_Freedom_Trail
- 思路1
0516_Longest_Palindromic_Subsequence
- slt
0518_Coin_Change_2
- Solution 1 DP
0520_Detect_Capital
- Solution1 遍历统计
0521_Longest_Uncommon_Subsequence_I
- Solution1 规律法
0523_Continuous_Subarray_Sum
- Solution1 前缀和 + hash + 同余
0524_Longest_Word_in_Dictionary_through_Deleting
- Solution 1 双指针检查 subsequence
0525_Contiguous_Array
- Solution1 hash
0526_Beautiful_Arrangement
- Solution1 回溯
0528_Random_Pick_with_Weight
- Solution1 前缀和 + 二分查找
0530_Minimum_Absolute_Difference_in_BST
- Solution1 中序遍历
0534_Game_Play_Analysis_III
- Solution 1
0538_Convert_BST_to_Greater_Tree
- Solution 1 right-mid-left traverse
0540_Single_Element_in_a_Sorted_Array
- Solution 1 二分
0541_Reverse_String_II
- Solution 1 遍历
0542_01_Matrix
- 思路1 dp
0543_Diameter_of_Binary_Tree
- Solution1 dfs 获取高度
0547_Number_of_Provinces
- 思路1 并查集
0550_Game_Play_Analysis_IV
- 思路1
0551_Student_Attendance_Record_I
- Solution1 遍历模拟
0552_Student_Attendance_Record_II
- Solution1 DP
0556_Next_Greater_Element_III
- 思路1 利用单调栈
0559_Maximum_Depth_of_N-ary_Tree
- Solution1 dfs
0560_Subarray_Sum_Equals_K
- 思路1 前缀和 + hash
0561_Array_Partition_I
- Solution1 Sort
0563_Binary_Tree_Tilt
- Solution1 dfs
0566_Reshape_the_Matrix
- Solution1 Traverse
0567_Permutation_in_String
- 思路1 滑动窗口 + hash
0570_Managers_with_at_Least_5_Direct_Reports
- 思路1
0572_Subtree_of_Another_Tree
- Solution1 preorder dfs
0574_Winning_Candidate
- slt
0575_Distribute_Candies
- Solution 1 hash
0577_Employee_Bonus
- 思路1
0578_Get_Highest_Answer_Rate_Question
- 思路1
0580_Count_Student_Number_in_Departments
- 思路1
0581_Shortest_Unsorted_Continuous_Subarray
- Solution1 贪心 + 双指针
0583_Delete_Operation_for_Two_Strings
- Solution1 DP
0584_Find_Customer_Referee
- 思路1
0585_Investments_in_2016
- 思路1 利用子查询
0586_Customer_Placing_the_Largest_Number_of_Orders
- 思路1
0595_Big_Countries
- 思路1
0596_Classes_More_Than_5_Students
- 思路1
0597_Friend_Requests_I:_Overall_Acceptance_Rate
- 思路1
0602_Friend_Requests_II:_Who_Has_the_Most_Friends
- 思路1 使用UNION ALL
0603_Consecutive_Available_Seats
- 思路1
0605_Can_Place_Flowers
- Solution1 greedy
0607_Sales_Person
- 思路1
0608_Tree_Node
- 思路1 left join + case when
0610_Triangle_Judgement
- 思路1
0611_Valid_Triangle_Number
- Solution1 双指针
0612_Shortest_Distance_in_a_Plane
- 思路1 JOIN计算每两点之间的距离
0613_Shortest_Distance_in_a_Line
- 思路1
0614_Second_Degree_Follower
- 思路1
0617_Merge_Two_Binary_Trees
- Solution 1 pre order dfs
0619_Biggest_Single_Number
- 思路1
0620_Not_Boring_Movies
- 思路1
0626_Exchange_Seats
- 思路1
0627_Swap_Salary
- 思路1
0629_K_Inverse_Pairs_Array
- Solution 1 DP + presum
0633_Sum_of_Square_Numbers
- Solution1 two-pointers
0637_Average_of_Levels_in_Binary_Tree
- Solution 1 bfs
0639_Decode_Ways_II
- Solution1 dp + by cases
0643_Maximum_Average_Subarray_I
- slt
0646_Maximum_Length_of_Pair_Chain
- Solution 1 DP
0649_Dota2_Senate
- 思路1 贪心，用队列来模拟投票
0650_2_Keys_Keyboard
- Solution 1 dp
0653_Two_Sum_IV_-_Input_is_a_BST
- Solution 1 in-order dfs + hash
0659_Split_Array_into_Consecutive_Subsequences
- 思路1 哈希表 + 最小堆
0661_Image_Smoother
- Solution 1 traverse + simulation
0664_Strange_Printer
- Solution1 DP
0665_Non-decreasing_Array
- 思路1 贪心
0669_Trim_a_Binary_Search_Tree
- Solution 1 dfs + BST 性质
0671_Second_Minimum_Node_In_a_Binary_Tree
- Solution1 dfs
0680_Valid_Palindrome_II
- Solution1 双指针
0684_Redundant_Connection
- 思路1 使用并查集
0692_Top_K_Frequent_Words
- Solution1 hash table + priority queue
0697_Degree_of_an_Array
- Solution1 Hash
0703_Kth_Largest_Element_in_a_Stream
- 思路1 优先队列
0704_Binary_Search
- 思路1 binary search
0714_Best_Time_to_Buy_and_Sell_Stock_with_Transaction_Fee
- 思路1 dp
0724_Find_Pivot_Index
- 思路1 前缀和
0725_Split_Linked_List_in_Parts
- Solution1 simulation
0726_Number_of_Atoms
- Solution1 stk + 从后往前，一次遍历
0738_Monotone_Increasing_Digits
- 思路1 贪心
0740_Delete_and_Earn
- Solution1 dp
0743_Network_Delay_Time
- Solution1 Dijkstra + 邻接矩阵
0746_Min_Cost_Climbing_Stairs
- 思路1 dp
0765_Couples_Holding_Hands
- Solution1 Greedy
0766_Toeplitz_Matrix
- Solution1 Traverse
0767_Reorganize_String
- 思路1 贪心法+最大堆
0783_Minimum_Distance_Between_BST_Nodes
- Solution1 中序遍历
0785_Is_Graph_Bipartite?
- Solution 1 BFS + 染色法
0786_K-th_Smallest_Prime_Fraction
- Solution 1 priority queue
0787_Cheapest_Flights_Within_K_Stops
- Solution1 DP
0789_Escape_The_Ghosts
- Solution1 贪心 + 曼哈顿距离
0797_All_Paths_From_Source_to_Target
- Solution1 DFS
0802_Find_Eventual_Safe_States
- Solution1 拓扑排序 + 反向图
0815_Bus_Routes
- Solution1 BFS
0820_Short_Encoding_of_Words
- 思路1 用一个set存储后缀
0830_Positions_of_Large_Groups
- 思路1 一次遍历，双指针
0832_Flipping_an_Image
- Solution1 Simulation
0842_Split_Array_into_Fibonacci_Sequence
- 思路1 回溯
0847_Shortest_Path_Visiting_All_Nodes
- Solution1 BFS
0852_Peak_Index_in_a_Mountain_Array
- Solution1 遍历
0859_Buddy_Strings
- Solution 1 simulation
0860_Lemonade_Change
- 思路1 一次遍历，记录5和10的个数
0861_Score_After_Flipping_Matrix
- 思路1 贪心
0863_All_Nodes_Distance_K_in_Binary_Tree
- Solution1 建图 + BFS
0867_Transpose_Matrix
- Solution1 Traverse
0869_Reordered_Power_of_2
- Solution 1 hash
0872_Leaf-Similar_Trees
- Solution1 Traverse
0876_Middle_of_the_Linked_List
- 思路1 快慢指针
0877_Stone_Game
- Solution1 DP
0879_Profitable_Schemes
- Solution1 DP
0881_Boats_to_Save_People
- Solution1 双指针 + 贪心
0882_Reachable_Nodes_In_Subdivided_Graph
- 同239
0887_Super_Egg_Drop
- 思路1 dp 逆向思维
0888_Fair_Candy_Swap
- 思路1 hash
0889_Construct_Binary_Tree_from_Preorder_and_Postorder_Traversal
- Solution 1 from root to leaf build tree
0892_Surface_Area_of_3D_Shapes
- 思路1
0897_Increasing_Order_Search_Tree
- Solution 1 in-order dfs
0912_Sort_an_Array
- 思路1 快排
0914_X_of_a_Kind_in_a_Deck_of_Cards
- 思路1 统计各个数出现的次数，然后求次数之间是否存在公约数
0922_Sort_Array_By_Parity_II
- 思路1 两次遍历
0930_Binary_Subarrays_With_Sum
- Solution1 pre sum + hash
0938_Range_Sum_of_BST
- Solution1 pre-order traverse
0941_Valid_Mountain_Array
- 思路1 遍历一遍
0945_Minimum_Increment_to_Make_Array_Unique
- 思路1 hash的思想用一个数字来记录重复出现的数字的个数
0959_Regions_Cut_By_Slashes
- 思路1 并查集
0973_K_Closest_Points_to_Origin
- 思路1 暴力计算
0976_Largest_Perimeter_Triangle
- 思路1
0978_Longest_Turbulent_Subarray
- 思路1 dp
0981_Time_Based_Key-Value_Store
- Solution 1 hash map + map
0993_Cousins_in_Binary_Tree
- Solution1 DFS
0995_Minimum_Number_of_K_Consecutive_Bit_Flips
- Solution1 Sliding Window
0999_Available_Captures_for_Rook
- 思路1
1004_Max_Consecutive_Ones_III
- Solution1 Sliding window
1005_Maximize_Sum_Of_Array_After_K_Negations
- Solution 1 贪心模拟
1006_Clumsy_Factorial
- Solution1 stack
1011_Capacity_To_Ship_Packages_Within_D_Days
- Solution1
1025_Divisor_Game
- Solution1 数学方法
1030_Matrix_Cells_in_Distance_Order
- 思路1 bfs
1035_Uncrossed_Lines
- Solution1 dp
1045_Customers_Who_Bought_All_Products
- 思路1
1046_Last_Stone_Weight
- 思路1 最大堆
1049_Last_Stone_Weight_II
- Solution1 DP
1050_Actors_and_Directors_Who_Cooperated_At_Least_Three_Times
- 思路1
1052_Grumpy_Bookstore_Owner
- Solution1 Sliding window
1059_All_Paths_from_Source_Lead_to_Destination
- Solution1 DFS
1068_Product_Sales_Analysis_I
- 思路1
1069_Product_Sales_Analysis_II
- 思路1
1070_Product_Sales_Analysis_III
- 思路1 利用子查询
1074_Number_of_Submatrices_That_Sum_to_Target
- Solution1 前缀和 + hash 表优化
1075_Project_Employees_I
- 思路1
1076_Project_Employees_II
- 思路1
1077_Project_Employees_III
- 思路1
1082_Sales_Analysis_I
- 思路1
1083_Sales_Analysis_II
- 思路1
1084_Sales_Analysis_III
- 思路1 用子查询
1098_Unpopular_Books
- 思路1
1104_Path_In_Zigzag_Labelled_Binary_Tree
- Solution1 二叉树性质
1107_New_Users_Daily_Count
- 思路1
1109_Corporate_Flight_Bookings
- slt
1110_Delete_Nodes_And_Return_Forest
- Solution 1 DFS + hash
1111_Maximum_Nesting_Depth_of_Two_Valid_Parentheses_Strings
- 思路1
1112_Highest_Grade_For_Each_Student
- 思路1
1113_Reported_Posts
- 思路1
1122_Relative_Sort_Array
- 思路1 双重循环
1126_Active_Businesses
- 思路1
1128_Number_of_Equivalent_Domino_Pairs
- slt
1132_Reported_Posts_II
- 思路1
1135_Connecting_Cities_With_Minimum_Cost
- Solution1 Kruskal 算法
1141_User_Activity_for_the_Past_30_Days_I
- 思路1
1142_User_Activity_for_the_Past_30_Days_II
- 思路1 使用distinct直接计算
1143_Longest_Common_Subsequence
- Solution 1 DP
1148_Article_Views_I
- 思路1
1162_As_Far_from_Land_as_Possible
- 思路1 BFS
1173_Immediate_Food_Delivery_I
- 思路1
1178_Number_of_Valid_Words_for_Each_Puzzle
- slt
1179_Reformat_Department_Table
- 思路1
1190_Reverse_Substrings_Between_Each_Pair_of_Parentheses
- Solution1 模拟 + 栈
1202_Smallest_String_With_Swaps
- 思路1 并查集
1203_Sort_Items_by_Groups_Respecting_Dependencies
- 思路1 拓扑排序
1207_Unique_Number_of_Occurrences
- 思路1 map + set
1208_Get_Equal_Substrings_Within_Budget
- 思路1 滑动窗口
1211_Queries_Quality_and_Percentage
- 思路1
1218_Longest_Arithmetic_Subsequence_of_Given_Difference
- Solution 1 DP
1221_Split_a_String_in_Balanced_Strings
- Solution 1 贪心
1232_Check_If_It_Is_a_Straight_Line
- 思路1 检查斜率
1241_Number_of_Comments_per_Post
- 思路1
1251_Average_Selling_Price
- 思路1
1269_Number_of_Ways_to_Stay_in_the_Same_Place_After_Some_Steps
- Solution1 DP
1280_Students_and_Examinations
- 思路1
1294_Weather_Type_in_Each_Country
- 思路1
1303_Find_the_Team_Size
- 思路1
1310_XOR_Queries_of_a_Subarray
- Solution1 前缀和
1322_Ads_Performance
- 思路1
1327_List_the_Products_Ordered_in_a_Period
- 思路1
1350_Students_With_Invalid_Departments
- 思路1
1370_Increasing_Decreasing_String
- 思路1 桶技术
1378_Replace Employee_ID_With_The_Unique_Identifier
- 思路1 left join
1418_Display_Table_of_Food_Orders_in_a_Restaurant
- Solution1 hash
1438_Longest_Continuous_Subarray_With_Absolute_Diff_Less_Than_or_Equal_to_Limit
- Solution1 Sliding window + Ordered Sequence
1442_Count_Triplets_That_Can_Form_Two_Arrays_of_Equal_XOR
- Solution1 前缀和 + 暴力
1486_XOR_Operation_in_an_Array
- Solution1 遍历一遍
1579_Remove_Max_Number_of_Edges_to_Keep_Graph_Fully_Traversable
- 思路1 并查集
1600_Throne_Inheritance
- Solution1 字典 + 链表
1603_Design_Parking_System
- Solution1 hash
1631_Path_With_Minimum_Effort
- 思路1 dijkstra算法变种
1646_Get_Maximum_in_Generated_Array
- Solution1 模拟遍历
1711_Count_Good_Meals
- Solution1 hash
1720_Decode_XORed_Array
- 思路1 反向异或
1721_Swapping_Nodes_in_a_Linked_List
- 思路1 双指针
1722_Minimize_Hamming_Distance_After_Swap_Operations
- 思路1 并查集
1723_Find_Minimum_Time_to_Finish_All_Jobs
- 思路1 dfs暴力破解 + 剪枝
1734_Decode_XORed_Permutation
- Solution1 数学模拟
1738_Find_Kth_Largest_XOR_Coordinate_Value
- Solution1 前缀和 + 最小堆
1744_Can_You_Eat_Your_Favorite_Candy_on_Your_Favorite_Day?
- Solution1 模拟 + 前缀和
1746_Maximum_Subarray_Sum_After_One_Operation
- Solution1 DP
1770_Maximum_Score_from_Performing_Multiplication_Operations
- Solution1 DP
1787_Make_the_XOR_of_All_Segments_Equal_to_Zero
- Solution1 DP
1833_Maximum_Ice_Cream_Bars
- Solution1 greedy
1838_Frequency_of_the_Most_Frequent_Element
- Solution1 前缀和 + 二分
1846_Maximum_Element_After_Decreasing_and_Rearranging
- Solution1 排序 + 遍历模拟
1877_Minimize_Maximum_Pair_Sum_in_Array
- Solution1 排序 + 模拟
1893_Check_if_All_the_Integers_in_a_Range_Are_Covered
- Solution1 贪心
1894_Find_the_Student_that_Will_Replace_the_Chalk
- Solution1 求模 + 模拟
mst01.07_Rotate_Matrix_LCCI
- 思路1 先上下翻转，再转置
mst02.05_Sum_Lists_LCCI
- 思路1 直接遍历计算
mst10.01_Sorted_Merge_LCCI
- 思路1
mst16.15_Master_Mind_LCCI
- 思路1 双hash
mst16.16_Sub_Sort_LCCI
- 思路1 双指针
mst16.17_Contiguous_Sequence_LCCI
- 思路1 dp
mst16.20_T9_LCCI
- 思路1 hash
mst16.21_Sum_Swap_LCCI
- 思路1 hash
mst16.22_Langtons_Ant_LCCI
- Solution 1 Simulation
mst16.24_Pairs_With_Sum_LCCI
- Solution1 Hash
mst17.04_Missing_Number_LCCI
- Solution1 xor
mst17.14_Smallest_K_LCCI
- Solution1 排序
mst17.16_The_Masseuse_LCCI
- 思路1 dp
mst17.21_Volume_of_Histogram_LCCI
- Solution1

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0331_Verify_Preorder_Serialization_of_a_Binary_Tree

Solution1 计算出度和入度

在有向图中，出度和入度是相等的。

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