Easy Level

1. Converting Decimal Number lying between 1 to 3999 to Roman Numerals
2. Find all triplets with zero sum
3. Largest subset whose all elements are Fibonacci numbers
4. Calculate maximum value using ‘+’ or ‘*’ sign between two numbers in a string
5. Convert Ternary Expression to a Binary Tree
6. Converting Roman Numerals to Decimal lying between 1 to 3999
7. Count all distinct pairs with difference equal to k
8. Decode a string recursively encoded as count followed by substring
9. Find if string is K-Palindrome or not | Set 2
10. Find Minimum Depth of a Binary Tree
11. Find subarray with given sum | Set 1 (Nonnegative Numbers)
12. Given two unsorted arrays, find all pairs whose sum is x
13. Greedy Algorithms | Set 1 (Activity Selection Problem)
14. Look-and-Say Sequence
15. Smallest subarray with sum greater than a given value
16. Program to add two binary strings
17. Rearrange a string in sorted order followed by the integer sum

Medium Level

1. Boggle | Set 2 (Using Trie)
2. Count Possible Decodings of a given Digit Sequence
3. Inplace rotate square matrix by 90 degrees | Set 1
4. Largest Rectangular Area in a Histogram | Set 2
5. Largest sum subarray with at-least k numbers
6. Multiply Large Numbers represented as Strings

Hard Level

1. Median in a stream of integers (running integers)