Given a number n, find the sum of all n-digit palindromes.
Given that an "even word" is a word in which each character appears an even number of times, write a function that takes in a string and returns the minimum number of letters to be removed to make that string an even word.
Given a decimal number as N, convert N into an equivalent irreducible fraction. An irreducible fraction is a fraction in which numerator and denominator are co-primes i.e., they have no other common divisor other than 1.
Sort an array of strings based on the number of distinct characters that occur in the word (followed by the length of the word)