SDE - 2

You are given the root node of a binary tree with N nodes, whose nodes have integer values. Your task is to find the maximum depth of the given Binary tree.

Depth of a binary tree is the same as its height. In simpler terms, you have to find the total number of nodes encountered while moving from the root node to the farthest leaf node, along the longest path of the binary tree.

Example:-

If we are given the above binary tree as input then moving from root node(5) to the farthest leaf node(50), the path formed will be [ 5->10->25->35->40->45->50 ]. The total number of nodes encountered is 7, therefore the maximum depth of the binary tree is 7.

Given an array/list of integers of length ‘N’, there is a sliding window of size ‘K’ which moves from the beginning of the array, to the very end. You can only see the ‘K’ numbers in a particular window at a time. For each of the 'N'-'K'+1 different windows thus formed, you are supposed to return the maximum element in each of them, from the given array/list.

Given a string (STR) of length N, you have to create a new string by performing the following operation:

Take the smallest character from the first 'K' characters of STR, remove it from STR and append it to the new string.

You have to perform this operation until STR is empty.

 Note:

The input string(STR) will not contain any spaces.

Assume that all characters in STR are lower case letters.

If characters less than 'K' remain, then append them in a sorted way to the new string.

Example:

Let the input string be "edcba" with K = 4.

Let the new string to be formed is initially empty, newString = "".
The first set of 4 characters are, ('e', 'd', 'c', 'b')
Out of these 4 characters, the smallest one is 'b' and hence we add it to the newString and it becomes, 
newString = "b"

The next set of 4 characters are, ('e', 'd', 'c', 'a')
Out of these 4 characters, the smallest one is 'a' and hence we add it to the newString and it becomes, 
newString = "ba"

Now we are left with "edc" and since we can't get a window of size 4, we sort them in the increasing order and append them to the newString.

Hence, newString thus formed will be "bacde".

You are given an array of N elements. This array represents the digits of a number. In an operation, you can swap the value at any two indices. Your task is to find the maximum number by using operation at most once.

For Example :

Input array [1,3,2,7] so basically this array represents the number 1327.
All the possible combinations are :
1. [3 1 2 7] get by swapping indices 1 and 2.
2. [2 3 1 7] get by swapping indices 1 and 3.
3. [7 3 2 1] get by swapping indices 1 and 4.
4. [1 2 3 7] get by swapping indices  2 and 3.
5. [1 7 2 3] get by swapping indices 2 and 4.
6. [1 3 7 2] get by swapping indices 3 and 4.
Out of all the possible combinations, 3 give the maximum number as 7321, so we will return [7 3 2 1].

Note :

The input may have 0 before the most significant digit. e.g. [0,3,5,7] is a valid input and this represents number 357.

You are given an array Arr consisting of N integers. You need to find the equilibrium index of the array.

An index is considered as an equilibrium index if the sum of elements of the array to the left of that index is equal to the sum of elements to the right of it.

Note:

1. The array follows 0-based indexing, so you need to return the 0-based index of the element.
2. Note that the element at the equilibrium index won’t be considered for either left sum or right sum.
3. If there are multiple indices which satisfy the given condition, then return the left-most index i.e if there are indices i,j,k…. which are equilibrium indices, return the minimum among them
4. If no such index is present in the array, return -1.