Solution Iterate from 1 to given number. Add each iteration to sum and square of it to another sum.

Solution Iterate from the given number to zero. Check if current iteration is a palindrome by using reverse() of StringBuilder class.

Solution Find all the factors of the given number by iterating from 1 to square root of the number.

Solution #1 Test cases 2,3 timed out for below solution.

Solution Count characters of each group in given string. Groups: digit, lower-case, upper-case and special characters Add one of each group to the string if not already present i.

Solution Graph is used to connect all astronauts to a country.

Minimum Cost If the number of roads is zero or cost of building a road is more than cost of building a library, then building libraries in each of the cities will result in minimum cost.