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)