SDE - 1

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.

You are given a 'Binary Tree'.

Return the bottom view of the binary tree.

Note :

1. A node will be in the bottom-view if it is the bottom-most node at its horizontal distance from the root. 

2. The horizontal distance of the root from itself is 0. The horizontal distance of the right child of the root node is 1 and the horizontal distance of the left child of the root node is -1. 

3. The horizontal distance of node 'n' from root = horizontal distance of its parent from root + 1, if node 'n' is the right child of its parent.

4. The horizontal distance of node 'n' from root = horizontal distance of its parent from the root - 1, if node 'n' is the left child of its parent.

5. If more than one node is at the same horizontal distance and is the bottom-most node for that horizontal distance, including the one which is more towards the right.

Example:

Input: Consider the given Binary Tree:

Output: 4 2 6 3 7

Explanation:
Below is the bottom view of the binary tree.

1 is the root node, so its horizontal distance = 0.
Since 2 lies to the left of 0, its horizontal distance = 0-1= -1
3 lies to the right of 0, its horizontal distance = 0+1 = 1
Similarly, horizontal distance of 4 = Horizontal distance of 2 - 1= -1-1=-2
Horizontal distance of 5 = Horizontal distance of 2 + 1=  -1+1 = 0
Horizontal distance of 6 = 1-1 =0
Horizontal distance of 7 = 1+1 = 2

The bottom-most node at a horizontal distance of -2 is 4.
The bottom-most node at a horizontal distance of -1 is 2.
The bottom-most node at a horizontal distance of 0 is 5 and 6. However, 6 is more towards the right, so 6 is included.
The bottom-most node at a horizontal distance of 1 is 3.
The bottom-most node at a horizontal distance of 2 is 7.

Hence, the bottom view would be 4 2 6 3 7

What is OOPS?

You are given a string 'str' of length 'N'. You can perform at most 'k' operations on this string. In one operation, you can choose any character of the string and change it to any other uppercase English alphabet character.

Return the length of the longest substring containing same characters after performing the above operations.

For example :

Input:
str="AABC"  k=1

Output:3

Explanation: Replace 'B' with 'A', we will get "AAAC" and the longest substring with same character is "AAA" of length 3.

You are given two strings, 'str1' and 'str2'. You have to find the length of the longest common substring.

A substring is a continuous segment of a string. For example, "bcd" is a substring of "abcd", while "acd" or "cda" are not.

Example:

Input: ‘str1’ = “abcjklp” , ‘str2’ = “acjkp”.

Output: 3

Explanation:  The longest common substring between ‘str1’ and ‘str2’ is “cjk”, of length 3.

Design a 3 elevator system for 8 floors

There are 100 doors in a row, all doors are initially closed. A person walks through all doors multiple times and toggle (if open then close, if close then open) them in the following way: 

In the first walk, the person toggles every door 

In the second walk, the person toggles every second door, i.e., 2^nd, 4^th, 6^th, 8^th, … 

In the third walk, the person toggles every third door, i.e. 3^rd, 6^th, 9^th, … 

Likewise,

In the 100^th walk, the person toggles the 100^th door. 

Which doors are open in the end? 

In a one day international cricket match, considering no extras(no wides, no ‘no’ balls, etc.) and no overthrows.

What is the maximum number of runs that a batsman can score in an ideal case ?