Problem solving challenges

Challenge	Solution	Difficulty
Solve me first	C, Java	Easy
Simple array sum	C	Easy
Compare the triplets	C	Easy
A very big sum	C	Easy
Diagonal difference	Python 3	Easy
Plus minus	Python 3	Easy
Staircase	Python 3	Easy
Mini-max sum	Python 3	Easy
Finding the percentage	Python 3	Easy
2D Array - DS	Python 3	Easy
Arrays: Left Rotation	Python 3, C	Easy
Birthday cake candles	C	Easy
Time conversion	Python 3, Java	Easy
The longest increasing subsequence	Python 3	Advanced
Extra long factorials	Python 3, C, Java	Medium
Grading students	Python 3	Easy
Apple and Orange	Python 3	Easy

Language specific challenges

Python
Merge the tools! (Medium) - Solution
Set .discard(), .remove(), .pop() (Easy) - Solution
Time delta (Medium) - Solution
Iterables and iterators (Medium) - Solution

C
Printing patterns with loops (Medium) - Solution

Java
If-Else (Easy) - Solution
Stdin and Stdout I (Easy) - Solution
Stdin and Stdout II (Easy) - Solution

Data Structures

Challenge	Language
Arrays - DS	C

30 Days of Code

Day	Language
0	Python 3, C, Java, Javascript, C++, C#, Ruby
1	Python 3, C, Java, Javascript, C++, C#, Ruby
2	Python 3, C, Java, Javascript, C++, C#, Ruby
3	Python 3, C, Java, Javascript, C++, C#, Ruby
4	Python 3, C (N/A), Java, Javascript, C++, C#, Ruby
5	Python 3, C, Java, Javascript, C++, C#, Ruby
6	Python 3, C, Java, Javascript, C++, C#, Ruby
7	Python 3, C, Java, Javascript, C++, C#, Ruby
8	Python 3