📈
notes
  • README
  • t
  • 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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  • 思路1 stack 直接把当前左括号对应的右括号入栈
  • 思路2 stack 把左括号入栈，遇到对应的右括号则弹出

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  1. 0020_Valid_Parentheses

slt

不管哪种方法，如果 长度是奇数，直接返回false

思路1 stack 直接把当前左括号对应的右括号入栈

注意括号交错要返回False

一种映射方法是只把右括号push入栈

思路2 stack 把左括号入栈，遇到对应的右括号则弹出

  • 时间复杂度 O(n)

  • 空间复杂度 O(n)

这是最容易想到的方法

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