SDE - 1

You are given a string S which represents a number. You have to find the smallest number strictly greater than the given number which contains the same set of digits as of the original number i.e the frequency of each digit from 0 to 9 should be exactly the same as in the original number.

For example:

If the given string is 56789, then the next greater number is 56798. Note that although 56790 is also greater than the given number it contains 1 '0' which is not in the original number and also it does not contain the digit '8'.

Note:

The given string is non-empty.

If the answer does not exist, then return -1.

The given number does not contain any leading zeros.

You are given two arbitrary binary trees consisting of N and M number of nodes respectively, your task is to check whether the two trees are mirror of each other or not.

Two trees are said to be mirror of each other, if

1. Roots of both the given trees are same.
2. Left subtree of the root of the first tree is the mirror of the right subtree of the root of the second tree.
3. Right subtree of the root of the first tree is the mirror of the left subtree of the root of the second tree.

For example,both the given trees are mirror image of each other: