LeetCode

Leetcode 解决方案

Solutions

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#	Solution	Tags	Difficulty	Remark
0001	Two Sum	Array,Hash Table	Easy
0002	Add Two Numbers	Recursion,Linked List,Math	Medium
0003	Longest Substring Without Repeating Characters	Hash Table,String,Sliding Window	Medium
0004	Median of Two Sorted Arrays	Array,Binary Search,Divide and Conquer	Hard
0005	Longest Palindromic Substring	String,Two Pointers,Dynamic Programming	Medium
0006	Zigzag Conversion	String	Medium
0007	Reverse Integer	Math	Medium
0008	String to Integer (atoi)	String	Medium
0009	Palindrome Number	Math	Easy
0010	Regular Expression Matching	Recursion,String,Dynamic Programming	Hard
0011	Container With Most Water	Greedy,Array,Two Pointers	Medium
0012	Integer to Roman	Hash Table,Math,String	Medium
0013	Roman to Integer	Hash Table,Math,String	Easy
0014	Longest Common Prefix	Trie,String	Easy
0015	3Sum	Array,Two Pointers,Sorting	Medium
0016	3Sum Closest	Array,Two Pointers,Sorting	Medium
0017	Letter Combinations of a Phone Number	Hash Table,String,Backtracking	Medium
0018	4Sum	Array,Two Pointers,Sorting	Medium
0019	Remove Nth Node From End of List	Linked List,Two Pointers	Medium
0020	Valid Parentheses	Stack,String	Easy
0021	Merge Two Sorted Lists	Recursion,Linked List	Easy
0022	Generate Parentheses	String,Dynamic Programming,Backtracking	Medium
0023	Merge k Sorted Lists	Linked List,Divide and Conquer,Heap (Priority Queue),Merge Sort	Hard
0024	Swap Nodes in Pairs	Recursion,Linked List	Medium
0025	Reverse Nodes in k-Group	Recursion,Linked List	Hard
0026	Remove Duplicates from Sorted Array	Array,Two Pointers	Easy
0027	Remove ELement from an Array	Array,Two Pointers	Easy
0028	Remove ELement from an Array	Array,Two Pointers	Easy
0029	Divide Two Integers	Math,Bit Manipulation	Medium
0035	Search Insert Position	Array,Binary Search	Easy
0038	Count And Say	String	Medium
0039	Combination Sum	Array,Backtracking	Medium
0046	Permutations	Array,Backtracking	Medium
0050	Pow(x, n)	Math,Recursion	Medium
0058	Length Of Last Word	String	Easy
0062	Unique Paths	Math, Dynamic Programming, Combinatorics	Medium
0023	Merge k Sorted Lists	Linked List,Divide and Conquer,Heap (Priority Queue),Merge Sort	Hard
0024	Swap Nodes in Pairs	Recursion,Linked List	Medium
0025	Reverse Nodes in k-Group	Recursion,Linked List	Hard
0023	Merge k Sorted Lists	Linked List,Divide and Conquer,Heap (Priority Queue)	Hard
0025	Reverse Nodes in k-Group	Recursion,Linked List	Hard
0031	Next Permutation	Array,Two Pointers	Medium
0034	Find First and Last Position of Element in Sorted Array	Array,Binary Search	Medium
0036	Valid Sudoku	Array,Hash Table,Matrix	Medium
0040	Combination Sum II	Array,Backtracking	Medium
0041	Smallest Positive NUmber	Array,Hash Table	Hard
0042	Trapping Rain Water	Array,Two Pointers,Dynamic Programming, Stack, Monotonic Stack	Hard
0049	Group Anagrams	Array,Hash Table,String, Sorting	Medium
0064	Minimum Sum Path	Array,Dynamic Programming,Matrix	Medium
0065	Valid Number	String	Hard
0067	Add Binary	Math,Binary Search	Easy
0069	Sqrt(x)	Math, Sring, Bit Manipulation, Simulation	Easy
0075	Sort Colors	Array, Two Pointers, Sorting	Medium
0077	Combinations	BackTracking	Medium
0078	Subsets	Array,Backtracking,Bit Manipulation	Medium
0083	Remove Duplicates from Sorted List	Linked List	Easy
0087	Scramble String	String, Dynamic Programming	Easy
0088	Merge Sorted Arrays	Array, Two Pointers, Sorting	Easy
0093	Restore IP Addresses	String, Backtracking	Medium
0094	Binary Tree Inorder Traversal	Stack, Tree, Depth-First Search, Binary Tree	Easy
0096	Unique Binary Search Trees	Math, Dynamic Programming, Tree, Binary Search Tree, Binary Tree	Medium
0097	Interleaving String	String, Dynamic Programming	Medium
0100	Same Tree	Tree, Depth-First Search, Breadth-First Search, Binary Tree	Easy
0108	Convert Sorted Array To Binary Search Tree	Array,Divide and Conquer, Tree, ``Binary Search Tree, Binary Tree`	Easy
0112	Path Sum	Breadth-First Search,Depth-First Search, Tree, ``Binary Search Tree, Binary Tree`	Easy
0118	Pascal Traingle	Array, Dynamic Programming	Easy
0119	Pascal Triangle II	Array, Dynamic Programming	Easy
0136	Single Number	Array, Bit Manipulation	Easy
0151	Reverse Words in a String	Two Pointers, Strings	Medium
0160	Intersection of Two Linked Lists	Two Pointers, Hash Table, Linked List	Easy
0169	Majority Element	Array, Hash Table, Sorting, Divide and Conquer, Counting	Easy
0175	Combine Two Tables	Database	Easy
0181	Employees Earning More Than Their Managers	Database	Easy
0182	Duplicate Emails	Database	Easy
0183	Customers Who Never Order	Database	Easy
0184	Duplicate Emails	Database	Easy
0185	Customers Who Never Order	Database	Easy
0190	Reverse Bits	Bit Manipulation, Divide and Conquer	Easy
0191	Number Of 1 Bits	Bit Manipulation, Divide and Conquer	Easy
0192	Word Frequency	Shell	Easy
0193	Valid Phone Numbers	Shell	Easy
0197	Rising Temperature	Database	Easy
0200	Number of Islands	Array, Depth-First Search, Breadth-First Search, Matrix	Medium
0205	Isomorphic Strings	Hash Table, String	Easy
0206	Reverse Linked List	Linked List, Recursion	Easy
0219	Contains Duplicate II	Array, Hash Table, Sliding Window	Easy
0222	Count Complete Tree Nodes	Tree, Binary Search, Bit Manipulation, Binary Tree	Easy
0226	Invert Binary Tree	Tree, Breadth-First Search, Depth-First Search, Binary Tree	Easy
0228	Summary Ranges	Array	Easy
0231	Power of Two	Math, Recursion, Bit Manipulation	Easy
0234	Palindrome Linked List	Linked List, Recursion, Two Pointers, Stack	Easy
0257	Binary Tree Paths	String,Tree, Backtracking, Depth-First Search, Binary Tree	Easy
0258	Add Digits	Math, Simulation, Number Theory	Easy
0263	Ugly Number	Math	Easy
0278	First Bad Version	Binary Search, Interactive	Easy
0279	Perfect Squares	Math, Dynamic Programming,Breadth-First Search	Medium
0292	Nim Game	Math, Brainteaser,Game Theory	Easy
0303	Range Sum Query - Immutable	Array, Design,Prefix Sum	Easy
0326	Power Of Three	Math, Recursion	Easy
0338	Counting Bits	Dynamic Programming, Bit Manipulation	Easy
0342	Power Of Four	Math, Recursion, Bit Manipulation	Easy
0345	Reverse Vowels Of A String	String, Two Pointers	Easy
0349	Intersection of Two Array	Array, Hash Table, Two Pointers, Binary Search, Sorting	Easy
0350	Intersection of Two Array II	Array, Hash Table, Two Pointers, Binary Search, Sorting	Easy
0367	Valid Perfect Square	Math, Binary Search	Easy
0374	Guess Number Higher or Lower	Binary Search, Interactive	Easy
0383	Ransom Note	Hash Table, String, Counting	Easy
0386	Lexical Order	Depth First Search, Tier	Medium
0389	Find the Difference	Hash Table, String, Bit Manipulation, Sorting	Easy
0392	Is Subsequence	Two Pointers, String, Dynamic Programming	Easy
0394	Decode String	String, Stack, Recursion	Medium
0404	Sum Of Left Leaves	Tree, Depth First Search, Breadth First Search, Binary Tree	Easy
0405	Convert a Number to a Hexadecimal	Math, Bit Manipulation	Easy
0409	Longest Palindrome	Hash Table, String, Greedy	Easy
0414	Third Max Number	Array, Sorting	Easy
0415	Add Strings	Math, String, Simulation	Easy
0440	K-th Smallest in Lexicographical Order	Trie	Hard
0463	Island Perimeter	Array, Depth-First Search, Breadth-First Search, Matrix	Easy
0476	Number Complement	Bit Manipulation	Easy
0485	Max Consecutive Ones	Array	Easy
0492	Construct The Rectangle	Math	Easy
0500	Keyboard Row	Array, Hash Table, String	Easy
0504	Base 7	Math	Easy
0506	Relative Ranks	Array, Sorting, Heap(Priority Queue)	Easy
0507	Perfect Number	Math	Easy
0509	Fibonacci Number	Array, Dynamic Programming, Breadth-First Search, Matrix	Easy
0511	Game Play Analysis I	Database	Easy
0520	Detect Capital	String,	Easy
0521	Longest Uncommon Subsequence I	String,	Easy
0541	Reverse String II	String, Two Pointers	Easy
0553	Optimal Division	Array, Math, Dynamic Programming	Easy
0557	Reverse Words in a String III	String, Two Pointers	Easy
0561	Array Partition	Array, Greedy, Sorting, Counting Sorting	Easy
0594	Longest Harmonious Subsequence	Array, Hash Table, Sliding Window, Sorting, Counting	Easy
0704	Binary Search	Array, Binary Search	Easy
0709	To Lower Case	String	Easy
0728	Self Dividing Numbers	Math	Easy
0821	Shortest Distance to a Character	Two Pointers,String,Array	Easy
0838	Push Dominoes	Two Pointers,String,Dynamic Programming	Easy
0844	Back String Compare	Two Pointers,String,Stack, Simulation	Easy
0905	Sort Array By Parity	Array, Two Pointers,Sorting	Easy
0976	Largest Perimeter Triangle	Array, Math, Greedy, Sorting	Easy
0977	Sorted Squares	Array, Two Pointers,Sorting	Easy
1013	Partition Array Into Three Parts With Equal Sum	Array,Greedy,	Easy
1025	Divisor Game	Math,Dynamic Programming, BrainTeaser, Game Theory	Easy
1045	Customers Who Bought All Products	Databases	Easy
1128	Number of Equivalent Domino Pairs	Array, Hash Table, Counting	Easy
1207	Unique Number of Occurrences	Array,Hash Table,	Easy
1208	Get Equal Substrings Within Budget	Strings,Binary Search,Sliding Window, Prefix Sum	Medium
1219	Path with Maximum Gold	Array,Backtracking,Matrix	Medium
1221	Split a String in Balanced Strings	String,Greedy,Counting	Easy
1394	Find Lucky Number in an Array	Array,Hash Table,Counting	Easy
1399	Count Largest Group	Hash Table, Math	Easy
1422	Maximum Score After Splitting A String	String,Prefix Sum	Easy
1534	Count Good Triplets	Array, Enumeration	Easy
1550	Three Consecutive Odds	Array	Easy
1636	Sort Array by Increasing Frequency	Array,Hash Table,Sorting	Easy
1695	Maximum Erasure Value	Array,Hash Table,Sliding Window,Weekly Contest 220	Medium
1700	Number of Students Unable to Eat Lunch	Array,Stack,Queue,Simulation	Easy
1752	Check if Array Is Sorted and Rotated	Array	Easy
1791	Find Center of Star Graph	Graph	Medium
1865	Finding Pairs With a Certain Sum	Array, Hash Table, Design	Medium
1913	Maximum Product Difference Between Two Pairs	Array, Sorting	Easy
1957	Delete Characters to Make Fancy String	String, Biweekly Contest 58	Easy
1984	Minimu Differences Between Highest & Lowest of K Scores	Array, Sliding Window, Sorting	Easy
2016	Maximum Difference Between Increasing Elements	Array	Easy
2044	Count Number of Maximum Bitwise-OR Subsets	Array, Backtracking, Bit Manipulation, Enumeration	Medium
2094	Finding 3-Digit Even Numbers	Array, Hash Table, Sorting, Enumeration	Easy
2114	Maximum Number of Words Found in Sentences	Array, String	Easy
2200	Find All K-Distant Indices in an Array	Array, Two Pointers	Easy
2309	Greatest English Letter in Upper and Lower Case	Hash Table, String, Enumeration	Easy
2396	Strictly Palindromic Number	Math, Two Pointers, Brainteaser	Medium
2406	Divide Intervals Into Minimum Number of Groups	Array,Greedy,Sorting,Two Pointers,Heap,Prefix Sum	Medium
2434	Using a Robot to Print the Lexicographically Smallest String	Hash Table,String,Stack,Greedy	Medium
2621	Sleep	JavaScript	Easy
2695	Array Wrapper	JavaScript, Array	Easy
2670	Find the Distinct Difference Array	Array,Hash Table	Easy
2707	Extra Characters in a String	Array, Hash Table, String, Dynamic Programming, Trie	Medium
2799	Count Complete Subarrays in an Array	Array, Hash Table, Sliding Window	Medium
2843	Count Symmetric Integeres	Math	Easy
2894	Divisible and Non-divisible Sums Difference	Math, Enumeration	Easy
2903	Find Indices With Index and Value Difference I	Array, Two Pointers	Easy
2929	Distribute Candies Among Children II	Math, Combinatronics, Enumeration	Easy
2942	Find Words Containing Character	Array, String	Easy
2960	Count Tested Devices After Test Operations	Array, Simulation, Count	Easy
2965	Find Missing and Repeated Values	Array, Hash Table, Math, Matrix	Easy
3024	Type of Triangle	Math,Array, Sorting	Easy
3034	Find the K-th Character in String Game I	Math,Bit Manipulation,Recursion, Simulation	Easy
3065	Minimum Operations to Exceed Threshold Value	Array	Easy
3074	Apple Redistribution into Boxes	Array,Greedy,Sorting	Medium
3075	Maximize Happiness of Selected Children	Array,Greedy,Sorting	Medium
3085	Minimum Deletions to Make String K-Special	Hash Table, String, Greedy,Sorting, Counting	Medium
3110	Score of a String	Array	Easy
3122	Minimum Number of Operations to Satisfy Conditions	Array	Easy
3136	Valid Word	String	Easy
3174	Clear Digits	String,Simulation, Stack	Easy
3201	Find the Maximum Length of Valid Subsequence I	Array, Dynamic Programming	Easy
3216	Lexicographically Smallest String After a Swap	String, Greedy	Easy
3304	Find the K-th Character in String Game I	Math,Bit Manipulation,Recursion, Simulation	Easy
3309	Maximum Possible Number by Binary Concatenation	Array,Bit Manipulation,Enumeration	Easy
3318	Find X-Sum of All K-Long Subarrays I	Array, Hash Table, Sliding Window, Heap	Easy
3330	Find the Original Typed String I	String	Easy
3340	Check Balanced String	String	Easy
3345	Smallest Divisible Digit Product I	Math	Easy
3355	Zero Array Transformation I	Array,Prefix Sum	Easy
3372	Maximize the Number of Target Nodes After Connecting Trees I	Tree, Depth-First-Search, Breadthth-First-Search	Easy
3407	Substring Matching Pattern	String, String Matching	Easy
3411	Maximum SubArray With Equal Products	Array, Math, Sliding Window, Enumeration, Number Theory	Easy
3421	Find Students Who Improved	Sql,	Easy
3439	Reschedule Meetings for Maximum Free Time I	Array, Hash Table, Sliding Window	Medium
3442	Maximum Difference Between Even and Odd Frequency I	Hash Table, String, Counting	Easy
3443	Maximum Manhattan Distance After K Changes	Hash Table, Math, String, Counting	Easy
3483	Unique 3-Digit Even Numbers	Array, Hash Table, Recursion, Enumeration	Easy
3502	Minimum Cost to Reach Every Position	Array,	Easy