Leetcode Solutions Swift

Leetcode solutions in Swift

Current Finished: 131

String(19)

Problem	Category	Difficulty	Space	Time
3 Longest Substring without repeating characters	String	Medium	O(n)	O(n)
14 Longest Common Prefix	String	Easy	O(nm)	O(mn)
28 Implement strStr	String	Easy	O(n)	O(mn)
49 Group Anagrams	String	Medium	O(Nmlgm)	O(N)
58 Length of Last Word	String	Easy	O(n)	O(n)
165 Compare Version Numbers	String	Easy	O(n)	O(n)
205 Isomorphic Strings	String	Easy	O(n)	O(n)
242 Valid Anagram	String	Easy	O(n)	O(n)
293 Flip Game 🔒	String	Easy	O(N)	O(N)
294 Flip Game 🔒	String	Medium	O(2^(n/2))	O(2^(n/2))
290 Word Pattern	String	Easy	O(n)	O(n)
340 Longest SubString with At Most K Distinct Characters 🔒	String	Hard	O(1)	O(N)
344 Reverse String	String	Easy	O(n)	O(n)
345 Reverse Vowels of a String	String	Easy	O(n)	O(n)
383 Ransom Note	String	Easy	O(n)	O(n)
388 Longest Absolute File Path Solution	String	Medium	O(N)	O(N)
389 Find the difference	String & hash table	Easy	O(n)	O(n)
394 Decode String	String	Medium	O(N)	O(N)
418 Sentence Screen Fitting 🔒	String	Medium	O(1)	O(row * col)

Array(22)

Problem	Category	Difficulty	Space	Time
1 Two Sum	Array	Easy	O(n)	O(n)
15 3Sum	Array	Medium	O(n)	O(n^2)
18 4Sum	Array	Medium	O(N^2)	O(N^4)
26 Remove Duplicates from sorted array	Array	Easy	O(N)	O(N)
27 Remove Element	Array	Easy	O(1)	O(n)
36 Valid Sudoku	Array	Easy	O(1)	O(1)
48 Rotate Image	Array	Medium	O(1)	O(n^2)
80 Remove Duplicates from sorted array II	Array	Medium	O(N)	O(N)
189 Rotate Array	Array	Easy	O(1)	O(n)
217 Contains Duplicate	Array	Easy	O(n)	O(n)
228 Summary Ranges	Array	Medium	O(n)	O(n)
260 Single Number III	Array/Bit	Medium	O(1)	O(n)
283 Move Zeroes	Array	Easy	O(1)	O(n)
303 Range Sum Query - Immutable	Array	Easy	O(N)	O(N)
304 Range Sum Query 2D - Immutable	Array	Medium	O(N^2)	O(N^2)
308 Range Sum Query 2D - Mutable	Array	Hard	O(N^2)	O(N^2)
349 Intersection of two arrays	Array	Easy	O(n)	O(n)
350 Intersection of two arrays II	Array	Easy	O(n)	O(n)
361 Bomb Enemy 🔒	Array	Medium	O(N)	O(MN)
457 Circular Array Loop	Array	Medium	O(1)	O(N)
621 Task Scheduler	Array	Medium	O(1)	O(N)
645 Set Mismatch	Array	Medium	O(N)	O(N)

Tree(20)

Problem	Category	Difficulty	Space	Time
98 Validate Binary Search Tree	Tree	Medium	O(n)	O(n)
100 Same Tree	Tree	Easy	O(n)	O(n)
101 Symmetric Tree	Tree	Easy	O(n)	O(n)
102 Binary Tree Level Order Traversal	Tree	Easy	O(n)	O(n)
104 Maximum Depth of Binary Tree	Tree	Easy	O(n)	O(n)
105 Construct Binary Tree From Preorder and InOorer Traversal	Tree	Medium	O(n)	O(n)
106 Construct Binary Tree From Inorder and Postorder Traversal	Tree	Medium	O(n)	O(n)
107 Binary Tree Level Order Traversal II	Tree	Easy	O(N)	O(N)
110 Balanced Binary Tree	Tree	Easy	O(n)	O(n)
111 Minimum Depth Of Binary Tree	Tree	Easy	O(n)	O(n)
112 Path Sum	Tree	Easy	O(n)	O(n)
113 Path Sum II	Tree	Medium	O(n)	O(n)
124 Binary Tree Maximum Path Sum	Tree	Hard	O(n)	O(n^2)(Memoized - O(n))
226 Invert Binary Tree	Tree	Easy	O(n)	O(n)
235 Lowest Common Ancestor of a Binary Search Tree	Tree	Medium	O(n)	O(n)
236 Lowest Common Ancestor of a Binary Tree	Tree	Medium	O(n)	O(n)
337 House Robber III	Tree	Medium	O(n)	O(n)
437 Path Sum III	Tree	Easy	O(n)	O(n)
450 Delete Node in a BST	Tree	Medium	O(1)	O(lgn)
655 Print Binary Tree	Tree	Medium	O(N)	O(N)

Graph(1)

Problem	Category	Difficulty	Space	Time
207 Course Schedule	Graph	Medium	O(	V

Search(9)

Problem	Category	Difficulty	Space	Time
33 Search in rotated sorted array	Search	Hard	O(1)	O(lgn)
34 Search for a Range	Search	Medium	O(1)	O(lgn)
35 Search Insert Position	Search	Medium	O(1)	O(lgn)
69 Sqrtx	Search	Medium	O(1)	O(lgn)
81 Search in rotated sorted array II	Search	Medium	O(1)	O(n)
153 Find Minimum in Rotated Sorted Array	Search	Medium	O(1)	O(lgn)
154 Find Minimum in Rotated Sorted Array II	Search	Medium	O(1)	O(n)
162 Find Peak Element	Search	Medium	O(1)	O(lgn)
278 First Bad Version	Binary Search	Easy	O(1)	O(lgn)

Linked List(8)

Problem	Category	Difficulty	Space	Time
2 Add Two Numbers	LinkedList	Medium	O(n)	O(n)
24 Swap Nodes in Pairs	Linked List	Easy	O(1)	O(n)
61 Rotate List	Linked List	Medium	O(1)	O(N)
83 Remove Duplicates From Sorted List	Linked List	Easy	O(1)	O(N)
86 Partition List	Linked List	Medium	O(1)	O(N)
141 Reorder List	Linked List	Medium	O(1)	O(N)
206 Reverse LinkedList	Linked List	Easy	O(1)	O(N)
445 Add Two Numbers II	Linked List	Medium	O(1)	O(N)

DynamicProgramming(18)

Problem	Category	Difficulty	Space	Time
5 Longest Palindromic Substring	DP	Medium	O(n^2)	O(n^2)
53 Maximum Subarray	DP	Medium	O(n)	O(n)
55 Jump Game	DP	Medium	O(n)	O(n)
62 Unique Paths	DP	Medium	O(mn)	O(mn)
63 Unique Paths II	DP	Medium	O(mn)	O(mn)
64 Minimum Path Sum	DP	Medium	O(mn)	O(mn)
70 Climbing Stairs	DP	Easy	O(1)	O(N)
72 Edit Distance	DP	Hard	O(NM)	O(NM)
121 Best Time to Buy and Sell Stock	DP	Easy	O(1)	O(N)
139 Word Break	DP	Medium	O(n)	O(nL^2)
152 Maximum Product Subarray	DP	Medium	O(1)	O(n)
198 House Robber	DP	Easy	O(n)	O(n)
213 House Robber II	DP	Medium	O(n)	O(n)
221 Maximal Square	DP	Medium	O(MN)	O(MN)
279 Unique Paths II	DP	Medium	O(n)	O(n^2)
300 Longest Increasing Subsequence	DP	Medium	O(n)	O(n^2)
322 Coin Change	DP	Medium	O(n^2)	O(n)
377 Combination Sum IV	Dynamic Programming	Medium	O(N)	O(n^(target/min(n)))

Stack(7)

Problem	Category	Difficulty	Space	Time
20 Valid Parentheses	Stack	Easy	O(N)	O(N)
94 Binary Tree In order Traversal	Stack	Medium	O(N)	O(N)
144 Binary Tree Preorder Traversal	Stack	Medium	O(N)	O(N)
145 Binary Tree Post Order Traversal	Stack	Hard	O(N)	O(N)
224 Basic Calculator	Stack	Hard	O(N)	O(N)
227 Basic Calculator II	Stack	Medium	O(N)	O(N)
772 Basic Calculator III	Stack	Hard	O(N)	O(N)

Heap(2)

Problem	Category	Difficulty	Space	Time
23 Merge K Sorted Lists	Heap	Hard	O(N)	O(Nlgk)
295 Find Median From Data Stream	Heap	Hard	O(N)	O(1)

Queue(1)

Problem	Category	Difficulty	Space	Time
346 Moving Average from Data Stream 🔒	Queue	Easy	O(N)	O(1)

Sort(3)

Problem	Category	Difficulty	Space	Time
75 Sort Colors	Sort	Medium	O(NlgN)	O(N)
347 Top K Frequent Element	Sort	Medium	O(klgk)	O(N)
56 Merge Intervals	Sort	Medium	O(NlgN)	O(N)

DFS(8)

Problem	Category	Difficulty	Space	Time
46 Permutations	DFS	Medium	O(N!)	O(N!)
47 Permutations II	DFS	Medium	O(N!)	O(N!)
77 Combinations	DFS	Medium	O(N^K)	O(K*N^K)
78 Subsets	DFS	Medium	O(2^N)	O(2^N)
79 Word Search	DFS	Medium	O(3^N)	O(N^2)
90 Subsets II	DFS	Medium	O(2^N)	O(2^N)
212 Word Search II	DFS	Hard	O(N*3^N)	O(N^2)
638 ShoppingOffers	DFS	Medium	O(N)	O(N^2)

BFS(1)

Problem	Category	Difficulty	Space	Time
317 Shortest Distance from All Buildings 🔒	BFS	Easy	O(MN)	O(KMN)

Math(11)

Problem	Category	Difficulty	Space	Time
7 Reverse Integer	Math	Easy	O(1)	O(1)
8 String to Integer(atoi)	Math String	Easy	O(n)	O(1)
9 Palindrome Number	Math	Easy	O(1)	O(1)
136 Single Number	Math	Easy	O(1)	O(n)
223 Rectangle Area	Math	Easy	O(1)	O(1)
231 Power of Two	Math	Easy	O(1)	O(1)
258 Add Digits	Math	Easy	O(1)	O(1)
263 Ugly Number	Math	Easy	O(1)	O(1)
326 Power of Three	Math	Easy	O(1)	O(1)
338 Counting Bits	Math	Medium	O(N)	O(N)
400 Nth Digit	Math	Easy	O(lgN)	O(1)

[Google]

Problem	Category	Difficulty	Space	Time
294 Flip Game 🔒	String	Medium	O(2^(n/2))	O(2^(n/2))
308 Range Sum Query 2D - Mutable	Array	Hard	O(N^2)	O(N^2)
317 Shortest Distance from All Buildings 🔒	BFS	Easy	O(MN)	O(KMN)
340 Longest SubString with At Most K Distinct Characters 🔒	String	Hard	O(1)	O(N)
346 Moving Average from Data Stream 🔒	Queue	Easy	O(N)	O(1)
361 Bomb Enemy 🔒	Array	Medium	O(N)	O(MN)
388 Longest Absolute File Path Solution	String	Medium	O(N)	O(N)
394 Decode String	String	Medium	O(N)	O(N)
418 Sentence Screen Fitting 🔒	String	Medium	O(1)	O(row * col)
482 LicenseKey Formatting Solution	String	Medium	O(n)	O(n)