lunaticf / leetcode

LeetCode solutions

leetCode

Java solutions of Leetcode

参考题目分类

Array

#	Title	Solution	Difficulty
26	Remove Duplicates from Sorted Array	code/note	Easy
27	Remove Element	code/note	Easy
35	Search Insert Position	code/note	Easy
54	Spiral Matrix	code/note	Medium
66	Plus One	code/note	Easy
88	Merge Sorted Array	code/note	Easy
118	Pascal's Triangle	code/note	Easy
119	Pascal's Triangle II	code/note	Easy
121	Best Time to Buy and Sell Stock	code/note	Easy
122	Best Time to Buy and Sell Stock 2	code/note	Easy
134	Gas Station	code/note	Medium
167	Two Sum II - Input array is sorted	code/note	Easy
169	Majority Element	code/note	Easy
189	Rotate Array	code/note	Easy
209	Minimum Size Subarray Sum	code/note	Easy
278	First Bad Version	code/note	Easy
283	Move Zeroes	code/note	Easy
299	Bulls and Cows	code/note	Medium
303	Range Sum Query - Immutable	code/note	Easy
374	Guess Number Higher or Lower	code/note	Easy
414	Third Maximum Number	code/note	Easy
448	Find All Numbers Disappeared in an Array	code/note	Easy
475	Heaters	code/note	Easy
485	Max Consecutive Ones	code/note	Easy
496	Next Greater Element I	code/note	Easy
498	Diagonal Traverse	code/note	Medium
506	Relative Ranks	code/note	Easy
532	K-diff Pairs in an Array	code/note	Easy
561	Array Partition I	code/note	Easy
581	Shortest Unsorted Continuous Subarray	code/note	Easy
566	Reshape the Matrix	code/note	Easy
605	Can Place Flowers	code/note	Easy
628	Maximum Product of Three Numbers	code/note	Easy
643	Maximum Average Subarray I	code/note	Easy
661	Image Smoother	code/note	Easy
674	Longest Continuous Increasing Subsequence	code/note	Easy
697	Degree of an Array	code/note	Easy
704	Binary Search	code/note	Easy
717	1-bit and 2-bit Characters	code/note	Easy
724	Find pivot index	code/note	Easy
733	Flood Fill	code/note	Easy
744	Find Smallest Letter Greater Than Target	code/note	Easy
747	Largest Number At Least Twice of Others	code/note	Easy

String

#	Title	Solution	Difficulty
13	Roman to Integer	code/note	Easy
14	Longest Common Prefix	code/note	Easy
28	Implement strStr()	code/note	Easy
38	Count and Say	code/note	Easy
58	Length of Last Word	code/note	Easy
67	Add Binary	code/note	Easy
151	Reverse Words in a String	code/note	Medium
242	Valid Anagram	code/note	Easy
344	Reverse String	code/note	Easy
345	Reverse Vowels of a String	code/note	Easy
383	Ransom Note	code/note	Easy
412	Fizz Buzz	code/note	Easy
415	Add Strings	code/note	Easy
434	Number of Segments in a String	code/note	Easy
443	String Compression	code/note	Easy
482	License Key Formatting	code/note	Easy
459	Repeated Substring Pattern	code/note	Easy
520	Detect Capital	code/note	Easy
521	Longest Uncommon Subsequence I	code/note	Easy
541	Reverse String II	code/note	Easy
551	Student Attendance Record I	code/note	Easy
557	Reverse Words in a String III	code/note	Medium
657	Robot Return to Origin	code/note	Easy
686	Repeated String Match	code/note	Easy
709	To Lower Case	code/note	Easy

hashTable

#	Title	Solution	Difficulty
1	Two Sum	code/note	Easy
3	Longest Substring Without Repeating Characters	code/note	Medium
36	Valid Sudoku	code/note	Medium
49	Group Anagrams	code/note	Medium
136	Single Number	code/note	Easy
202	Happy Number	code/note	Easy
205	Isomorphic Strings	code/note	Easy
217	Contains Duplicate	code/note	Easy
219	Contains Duplicate II	code/note	Easy
290	Word Pattern	code/note	Easy
347	Top K Frequent Elements	code/note	Medium
349	Intersection of Two Arrays	code/note	Easy
350	Intersection of Two Arrays II	code/note	Easy
380	Insert Delete GetRandom O(1)	code/note	Medium
387	First Unique Character in a String	code/note	Easy
389	Find the Difference	code/note	Easy
409	Longest Palindrome	code/note	Easy
447	Number of Boomerangs	code/note	Easy
454	4Sum II	code/note	Medium
500	Keyboard Row	code/note	Easy
594	Longest Harmonious Subsequence	code/note	Easy
575	Distribute Candies	code/note	Easy
599	Minimum Index Sum of Two Lists	code/note	Easy
645	Set Mismatch	code/note	Easy
652	Find Duplicate Subtrees	code/note	Medium
705	Design HashSet	code/note	Easy
706	Design HashMap	code/note	Easy
720	Longest Word in Dictionary	code/note	Easy
771	Jewels and Stones	code/note	Easy

Recursion

#	Title	Solution	Difficulty
21	Merge Two Sorted Lists	code/note	Easy
24	Swap Nodes in Pairs	code/note	Medium
50	Pow(x, n)	code/note	Medium
70	Climbing Stairs	code/note	Easy
95	Unique Binary Search Trees II	code/note	Medium
104	Maximum Depth of Binary Tree	code/note	Easy
206	Reverse Linked List	code/note	Easy
509	Fibonacci Number	code/note	Easy
779	K-th Symbol in Grammar	code/note	Medium

Tree

#	Title	Solution	Difficulty
94	Binary Tree Inorder Traversal	code/note	Medium
100	Same Tree	code/note	Easy
101	Symmetric Tree	code/note	Easy
102	Binary Tree Level Order Traversal	code/note	Medium
108	Convert Sorted Array to Binary Search Tree	code/note	Easy
110	Balanced Binary Tree	code/note	Easy
111	Minimum Depth of Binary Tree	code/note	Easy
112	Path Sum	code/note	Easy
114	Flatten Binary Tree to Linked List	code/note	Medium
144	Binary Tree Preorder Traversal	code/note	Medium
215	Kth Largest Element in an Array	code/note	Medium
235	Lowest Common Ancestor of a Binary Search Tree	code/note	Easy
257	Binary Tree Paths	code/note	Medium
226	Invert Binary Tree	code/note	Easy
337	House Robber III	code/note	Medium
404	Sum of Left Leaves	code/note	Easy
429	n-ary-tree-level-order-traversal	code/note	Easy
437	Path Sum III	code/note	Easy
501	Find Mode in Binary Search Tree	code/note	Easy
532	Minimum Absolute Difference in BST	code/note	Easy
538	Convert BST to Greater Tree	code/note	Easy
543	Diameter of Binary Tree	code/note	Easy
559	Maximum Depth of N-ary Tree	code/note	Easy
563	Binary Tree Tilt	code/note	Easy
572	Subtree of Another Tree	code/note	Easy
606	Construct String from Binary Tree	code/note	Easy
617	Merge Two Binary Trees	code/note	Easy
637	Average of Levels in Binary Tree	code/note	Easy
653	Two Sum IV - Input is a BST	code/note	Easy
669	Trim a Binary Search Tree	code/note	Easy
671	Second Minimum Node In a Binary Tree	code/note	Easy
700	Search in a Binary Search Tree	code/note	Easy

Math

#	Title	Solution	Difficulty
7	Reverse Integer	code/note	Easy
9	Palindrome Number	code/note	Easy
171	Excel Sheet Column Number	code/note	Easy
172	Factorial Trailing Zeroes	code/note	Easy
204	Count Primes	code/note	Easy
258	Add Digits	code/note	Easy
263	Ugly Number	code/note	Easy
278	Count Primes	code/note	Easy
292	Nim Game	code/note	Easy
292	Nim Game	code/note	Easy
326	Power of Three	code/note	Easy
342	Power of Four	code/note	Easy
441	Arranging Coins	code/note	Easy
453	Minimum Moves to Equal Array Elements	code/note	Easy
458	Poor Pigs	code/note	Hard
463	Island Perimeter	code/note	Easy
492	Construct the Rectangle	code/note	Easy
504	Base 7	code/note	Easy
507	Perfect Number	code/note	Easy
633	Sum of Square Numbers	code/note	Easy
728	Self Dividing Numbers	code/note	Easy
1025	Divisor Game	code/note	Easy

Bit

#	Title	Solution	Difficulty
190	Reverse Bits	code/note	Easy
191	Number of 1 Bits	code/note	Easy
231	Power of Two	code/note	Easy
268	Missing Number	code/note	Easy
338	Counting Bits	code/note	Medium
371	Sum of Two Integers	code/note	Medium
401	Binary Watch	code/note	Easy
405	Convert a Number to Hexadecimal	code/note	Easy
476	Number Complement	code/note	Easy
461	Hamming Distance	code/note	Easy
693	Binary Number with Alternating Bits	code/note	Easy

Dynamic Programming

#	Title	Solution	Difficulty
53	Maximum Subarray	code/note	Easy
64	Minimum Path Sum	code/note	Medium
139	Word Break	code/note	Medium
198	House Robber	code/note	Easy
213	House Robber II	code/note	Medium
279	Perfect Squares	code/note	Medium
300	Longest Increasing Subsequence	code/note	Medium
746	Min Cost Climbing Stairs	code/note	Easy
1027	Longest Arithmetic Sequence	code/note	Medium

Stack and Queue

#	Title	Solution	Difficulty
20	Valid Parentheses	code/note	Easy
71	Simplify Path	code/note	Medium
155	Min Stack	code/note	Easy
225	Implement Stack using Queues	code/note	Easy
232	Implement Queue using Stacks	code/note	Easy
682	Baseball Game	code/note	Easy

LinkedList

#	Title	Solution	Difficulty
83	Remove Duplicates from Sorted List	code/note	Easy
141	Linked List Cycle	code/note	Easy
160	Intersection of Two Linked Lists	code/note	Easy
203	Remove Linked List Elements	code/note	Easy
234	Palindrome Linked List	code/note	Easy
237	Delete Node in a Linked List	code/note	Easy

Backtracking

#	Title	Solution	Difficulty
17	Letter Combinations of a Phone Number	code/note	Medium
93	Restore IP Addresses	code/note	Medium

Sql

#	Title	Solution	Difficulty
175	Combine Two Tables	code	Easy
176	Second Highest Salary	code	Easy

graph

#	Title	Solution	Difficulty
1202	Smallest String With Swaps	code/note	Medium

Greedy

#	Title	Solution	Difficulty
455	Assign Cookies	code/note	Easy
680	Valid Palindrome II	code/note	Easy
754	Reach a Number	code/note	Easy