Solutions to the LeetCode May 2020 Challenge

Questions are pasted in the code as comments.

S No.	Problem Name	Algorithm / Data Structure	Time Complexity	Space Complexity
1	First Bad Version	Binary Search	O(logn)	O(1)
2	Jewels and Stones	HashSet	O(m+n)	O(m)
3	Ransom Note	MultiSet	O(m+n)	O(n)
4	Number Complement	Bit Manipulation	O(1)	O(1)
5	First Unique Character in a String	NA	O(n)	O(m)
6	Majority Element	Sort	O(n(logn))	O(1)
7	Cousins in Binary Tree	Recursion	O(n)	O(1)
8	Check If It Is a Straight Line	Slope Formula	O(n)	O(1)
9	Valid Perfect Square	Binary Search	O(logn)	O(1)
10	Find the Town Judge	HashMap	O(m+n)	O(n)
11	Flood Fill	DFS	O(n)	O(n)
12	Single Element in a Sorted Array	XOR	O(n)	O(1)
13	Remove K Digits	NA	O(n)	O(n)
14	Implement Trie (Prefix Tree)	Trie	O(m*n)	O(n)
15	Maximum Sum Circular Subarray	Kadene's Algo	O(n)	O(1)
16	Odd Even Linked List	Linked List	O(n)	O(1)
17	Find All Anagrams in a String	Modified Rabin Karp	O(n)	O(1)
18	Permutation in String	Modified Rabin Karp	O(n)	O(1)
19	Online Stock Span	Stack	O(n)	O(n)
20	Kth Smallest Element in a BST	Inorder Traversal	O(n)	O(n)
22	Sort Characters By Frequency	HashMap & VectorPair	O(logn)	O(n)
23	Interval List Intersections	NA	O(m+n)	O(m+n)
24	Construct Binary Search Tree from Preorder Traversal	BST	O(n^2)	O(n)
25	Uncrossed Lines	Dynamic Programming	O(n)	O(n)
26	Contiguous Array	Dynamic Programming	O(n)	O(n)
27	Possible Bipartition	DFS	O(n)	O(n)
28	Counting Bits	Bit Manipulation	O(logn)	O(1)
29	Course Schedule	Graph Coloring	O(v+e)	O(e)
30	K Closest Points to Origin	HashMap	O(n)	On)
31	Edit Distance	Dynamic Programming	O(n)	O(n)