Solve Three Algorithmic Problems

Let s be a string made of lowercase English letters. Consider all unique permutations of its characters; repeated letters that produce identical arrangements are counted once. Order these permutations lexicographically from largest to smallest. The largest permutation is obtained by arranging the characters in descending order. Return the permutation immediately below that largest one as a string. Example 1: Explanation: The unique permutations in descending order are "baa",…