Our objective is to find the smallest positive number that is missing from an unsorted array. We will be given an array a[] of both positive and negative numbers, we need to get the smallest positive number that is missing from an unsorted array in this problem. We can modify the array given in this problem to solve it. For example, INPUT : a[] = {5, 8, -13, 0, 18, 1, 3} OUTPUT : 2 INPUT : a[] = {7, 10, -8, 1, 4} OUTPUT : 2 In the above examples, we are given an unsorted array as an input. ... Read More

In this problem, we simply need to divide two integers without using multiplication, division and mod operator. Though we can use addition or multiplication or bit manipulation. The problem statement states that we will be given two integers x and y. Without using multiplication, division or mod operator, we need to determine the quotient after dividing x by y. Example INPUT: x=15 , y=5 OUTPUT: 3 INPUT: x=10 , y=4 OUTPUT: 2 INPUT: x=-20 , y=3 OUTPUT: -6 Approach Approach-1(using simple mathematics) In this approach, we will use a simple mathematics algorithm. Below is the step-by-step illustration of the ... Read More

A figurative number that depicts a dodecagon is called a dodecagonal number. The Centered Dodecagonal number is represented by a dot in the centre and other dots encircling it in the successive dodecagonal (i.e. a 12-sided polygon) layers. Centered Dodecagonal number can be better explained with the below figure. For n=1, only a single dot will be there in the centre. So the output will be 1. For n=2, a single dot in the centre followed by a dodecagon encircling it. Thus, the total number of dots will be 13. So the next centred dodecagonal number ... Read More

Strings are the storage elements for storing different kinds of letters and symbols. It is indicative of a stream of characters in C++. Strings are denoted in double quotes or single quotes. The given input string can be comprised of both uppercase and lowercase characters. The problem statement is to change the case of the characters of the string, in such a way that the letter which was originally written in lowercase is converted into uppercase and vice versa. Some of the examples illustrating the problem statement are as follows − Sample Examples Example 1 : "AbCd" Output : bAdC ... Read More

A Perfect Power is a Natural Number that is the product of equal natural factors. It can also be defined as an integer that can be expressed as a square power or a higher power of another integer greater than one. For example, 4 can be expressed as the product of 2*2. 27 can be expressed as the product of 3*3*3. Hence, 4 and 27 are perfect powers. Problem Statement Given a number n, find the count of perfect numbers which are less than or equal to n. Example 1 Input = 14 Output = 3 Explanation 1 ... Read More

The Legendre’s Conjecture states that at least one prime number always exists between two consecutive natural numbers' squares. Mathematically, there is always a prime number p between any two numbers n2 and (n+1)2. n is a natural number. A conjecture means a conclusion that doesn't has mathematical proof. Hence, Legendre's Conjecture is just a statement with no mathematical proof. Problem Statement For a number n, print the number of primes in the range of n2 to (n+1)2 from 1 to n. Examples Input: 4 Output: For i = 1: Total primes in the range 1 and 4 = 2 ... Read More

What are Corner digits? The corner digits of a number refer to the rightmost and the leftmost digits. For example, the corner digits of 1234 are 1 and 4. The corner digits of a single-digit number will be the number twice. For example, the corner digits of 2 will be 2 and 2. Problem Statement For given two numbers, n, and x, form a number using the corner digits of all the powers of n from 1 and x, i.e., n1, n2....nx. Examples Input: n = 2, x = 4 Output: 22448816 Explanation 21 = 2. Corner digits = ... Read More

Gray code or reflected binary code is a form of a binary representation of numbers in which two consecutive numbers only differ by one bit. For example, the gray code of 1 is 001, while the gray code of 2 is 011. Gray code is usually used in error correction because it prevents some data errors that can happen in the usual binary representations while state changes. Gray code is also helpful in k-maps, communication, etc., because of its unique property. Prerequisite Study decimal, binary and gray code notations before reading further. Problem Statement 1 Given a decimal number n, ... Read More

Cube-free numbers are those numbers that have no cubic divisors. A cubic divisor refers to an integer that is a cube and divides the number with zero remainders. For example, 8 is a cubic divisor of 16 since 8 is a cube of 2 (2*2*2 = 8), and 8 divides 16 with the remainder of zero. Thus, 8 and 16 both are not cube-free numbers. Problem Statement Find all the cube-free numbers less than a given number, n. Example Let's understand the problem with an example. Let n = 15, Thus, we have to find all the numbers less than ... Read More

A Square Pyramidal Number means the Sum of the Square of Natural Numbers. Natural Numbers include all the numbers from 1 to infinity. For example, the first 4 Square pyramidal numbers are 1, 5, 14, 30. For better perception, consider the fact: If we take spheres of numbers equal to the square pyramidal numbers, starting from one, and stack them in descending order, they create a pyramid. Problem Statement Given a number Sum. If Sum is the sum of the squares of first “n” natural numbers, return n, otherwise return false. Example 1 Input = 30 Output = 4 ... Read More