SDE - 1

You are given a string 'str' of length 'N'.

Your task is to reverse the original string word by word.

There can be multiple spaces between two words and there can be leading or trailing spaces but in the output reversed string you need to put a single space between two words, and your reversed string should not contain leading or trailing spaces.

Example :

If the given input string is "Welcome to Coding Ninjas", then you should return "Ninjas Coding to Welcome" as the reversed string has only a single space between two words and there is no leading or trailing space.

Given an array ‘arr’ of size ‘n’ find the largest element in the array.

Example:

Input: 'n' = 5, 'arr' = [1, 2, 3, 4, 5]

Output: 5

Explanation: From the array {1, 2, 3, 4, 5}, the largest element is 5.

You are given an integer ‘N’. You have to print the value of Factorial of ‘N’. The Factorial of a number ‘N’ is defined as the product of all numbers from 1 to ‘N’.

For Example:

Consider if ‘N’ = 4, the Factorial of 4 will be the product of all numbers from 1 to 4, which is 1 * 2 * 3 * 4 = 24. Hence, the answer is 24.

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.

You are given an integer ‘N’, your task is to find and return the N’th Fibonacci number using matrix exponentiation.

Since the answer can be very large, return the answer modulo 10^9 +7.

Fibonacci number is calculated using the following formula:

F(n) = F(n-1) + F(n-2), 
Where, F(1) = F(2) = 1.

For Example:

For ‘N’ = 5, the output will be 5.

Create a class to represent a circle with a given radius, and calculate its circumference and area.

Design a URL shortening service.

Select all records from a table where a particular column value equals a given value.

Implement a mutex lock using semaphores.

What inspired you to become a developer?