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There can be multiple combinations of numbers if taken 1 to n at a time. For example, if we take one number at a time, the number of combinations will be nC1. If we take two numbers at a time, the number of combinations will be nC2. Hence, the total number of combinations will be nC1 + nC2 +… + nCn. To find the sum of all combinations, we will have to use an efficient approach. Otherwise, the time and space complexities will go very high. Problem Statement Find the sum of products of all the combinations of numbers taken ... Read More
Sorting a vector using STL is a piece of cake. We can use the famous sort() function to perform the task. The real challenge is to count the number of factors for each number. A factor is a number which divides another number completely, i.e. with zero remainder. Traversing through all the numbers to count the factors might be an approach but we will try to optimize and reach efficient solutions in this article. Problem Statement Sort a given array based on the number of factors of each number in increasing order. Thus, the number having the lowest number of ... Read More
A number is p-friable for p-smooth if all of its prime factors are less than or equal to p. For example, 1620 is a 5-smooth number. Because, the prime factors of 1620 are: 2, 3, and 5. As it can be seen, 1620 is also a 7-smooth and 11-smooth number. Problem Statement Given two numbers N and P, we have to check if N is a P-friable number or not. Examples Input − N = 50, P = 7 Output − Yes, 50 is a 7-friable number. Explanation 50 can be prime factorized as: 5*5*5*5. Hence, ... Read More
Sometimes working with Python string, we may come across a real-world scenario where it can be useful for text parsing, pattern matching, and extracting specific information from text data. In Python, we have some built-in functions such as type(), index(), append(), and, isinstance() will be used to find the index containing String in List. Let’s take an example of this: The given input string, my_list = [108, 'Safari', 'Skybags', 20, 60, 'Aristocrat', 78, 'Raj'] Output 1, 2, 5, 7 Explanation The variable name my_list stores the input list that contains the mixing of integer and string in ... Read More
In this article, we will discuss different approaches to calculate the number of positive integers which have no repeated digits between a given range Low to high. The first approach is a brute force approach which iterates over all the numbers in the range and check if they contain repeated digits. In our second approach, we calculated the desired count using prefix array while in our last approach we used the concept of memorization in dynamic programming to get the desired result. Problem Statement: We are given two numbers low and high and we have to find the count of ... Read More
In this article, we will discuss what is Tomohiko Sakamoto’s algorithm and how this algorithm is used to identify which day of the week does the given date occurs. There are multiple algorithms to know the day of the week but this algorithm is the most powerful one. This algorithm finds the day of the month on which the date occurs in least possible time and least space complexity. Problem statement − We are given a date as per Georgian calendar and our task is to find out which day of the week occurs on the given date using ... Read More
In this article, we will discuss a few recursive practice problems with their detailed solutions. Let us first understand what recursion is and how it works: Recursion − Recursion is a programming technique in which a function or method calls itself multiple times in order to solve a problem. The function breaks down the problem into smaller sub-problems and solves them until it reaches a base case. The base case is a stopping condition that makes sure that the function stops calling itself and returns a result in finite time. Recursion is a powerful technique for solving complex ... Read More
In this article, we will discuss the code solution to swap every alternate bit in a given number and return the resultant number. We will use the concept of bit manipulation in order to solve the problem in constant time without using any loops. Problem statement − We are given a number n, we have to swap the pair of bits that are adjacent to each other. In other words, we have to swap every odd placed bit with its adjacent even placed bit. Constrain: While solving the problem, we have to keep In mind that we cannot use ... Read More
In this article, we will study different approaches to calculate the sum of the series- (n^2 - 1^2) + 2(n^2 - 2^2) + …. n(n^2 - n^2). In the first approach, we will calculate the series sum one by one for each i in the range 1 to n and keep adding it to the final sum. In the second approach, we will derive a mathematical formula to calculate the sum of the given series which will result in the reduced time complexity of the program from O(n) to O(1). Problem statement − We are given a number “n “and ... Read More
Collections in Java is a framework which provides classes and interfaces to manipulate group of objects. Collections help in storing and manipulating different types of objects in java. Size of the collection tells us how many elements are present in that particular collection. Java provides various collection classes namely ArrayList, LinkedList, HashSet, and TreeSet, among others. In this section, we are going to write a java program to get the size of collection and verify the collection is empty or not. The different types of collections in Java are − List − List is an ordered collection of objects ... Read More