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Data Structure Articles
Page 19 of 164
How to Decode the string encoded with the given algorithm?
Introduction Encoding means converting the text into some form of representation, and decoding is the process of converting the encoded text into its original form. Encoding and decoding are two interrelated techniques for transferring information from one form to another. In this tutorial, we implement an approach to decode the string which is encoded with the given algorithm that finds the decoded string using an encoded string encoded with some algorithm. The string is encoded using the following concept − For example string = India Encoded string = dniIa In the string "India", the middle character is 'd', ...
Read MoreHow to decrypt a string according to given algorithm?
Decryption or decrypt a string is the process used to protect confidential and sensitive data from hackers. It converts encrypted data or text into its original form. Encryption is the process of converting plain text into an unreadable and non-understandable cipher text format so that hackers cannot understand it. These processes are interrelated and involve various algorithms for processing. We decrypt the string according to the following algorithm. If the string length is odd. For odd index values append alphabets from the back of the string and for even index values append alphabets from the front of the input ...
Read MoreCount of all substrings with sum of weights at most K
Introduction In this tutorial, we discuss the problem of counting the substrings from a given string with the sum of weights at most K. To implement the problem statement we consider a string S to generate substrings and some value for k. The character weights are predefined integer values and we consider some value of K like 2, 3 or anything. We count only those substrings whose total weight is equal to the value of K. The weights of the characters are defined in two different ways − When the weights are defined for a string in any order. ...
Read MoreCheck whether the string can be printed using same row of qwerty keypad
Introduction In this tutorial, we will check if an input string can be formed using characters in the same row of the Qwerty keypad. The task is to check whether a given string exists in a single row of the Qwerty keypad. To determine whether a string can be printed with the same row of the Qwerty keypad, all characters should be found in the same row. We implement an approach using set and unordered_set to solve this task. The characters of different rows are stored in different sets or unordered_sets. Compare the string characters to each stored row value. ...
Read MoreCheck if a substring can be Palindromic by replacing K characters for Q queries
Introduction In this tutorial, we implement an approach to check substring is palindrome by replacing its K characters for Q queries. Palindromes are words that read the same in both directions. When you read a palindromic word from a forward or backward direction, it sounds the same. For example, madam, refer. Here, Q queries are a numeric array containing the starting index, ending index, and value of K. The starting and ending index values for the input string are used to select only those characters that lie between these starting and ending index values (both values are inclusive). For the ...
Read MoreSum of an array using pthreads
Pthreads is an execution model that helps use multiple processors to work at the same time for solving a problem. It is independent of the programming language. Problem Statement Given an array of integers. Find the sum of all the elements of the array using pthreads. Need for Multithreading for Calculating sum The problem is to add the elements in an array. Although it is a simple problem where a linear traversal of the array can do the work very easily with a time complexity of O(n) where n is the number of elements in the array. But if we ...
Read MorePrint numbers in the range 1 to n having bits in an alternate pattern
Alternate bit pattern implies the positioning of 0’s and 1’s in a number at an alternate position i.e. no two 0s or 1’s are together. For example, 10 in binary representation is (1010)2 which has an alternate bit pattern as 0’s and 1’s are separated by each other. Problem Statement Given an integer, N. Find all the integers in the range 1 to N where the bit pattern of the integer is alternating. Example 1 Input: 10 Output: 1, 2, 5, 10 Explanation $\mathrm{(1)_{10} = (1)_2, (2)_{10} = (10)_2, (5)_{10} = (101)_2, (10)_{10} = (1010)_2}$ Example 2 Input: ...
Read MoreJacobsthal and Jacobsthal-Lucas Numbers
Jacobsthal Numbers Lucas sequence 𝑈𝑛(𝑃, 𝑄) where P = 1 and Q = -2 are called Jacobsthal numbers. The recurrence relation for Jacobsthal numbers is, $$\mathrm{𝐽_𝑛 = 0\: 𝑓𝑜𝑟 \: 𝑛 = 0}$$ $$\mathrm{𝐽_𝑛 = 1\: 𝑓𝑜𝑟 \: 𝑛 = 1}$$ $$\mathrm{𝐽_𝑛 = 𝐽_𝑛−1 + 2𝐽_{𝑛−2}\: 𝑓𝑜𝑟 \: 𝑛 > 1}$$ Following are the Jacobsthal numbers − 0, 1, 1, 3, 5, 11, 21, 43, 85, 171, 341, 683, 1365, …. Jacobsthal-Lucas Numbers Complementary Lucas sequence $\mathrm{𝑉_𝑛(𝑃, 𝑄)}$ where P = 1 and Q = -2 are called JacobsthalLucas numbers. The recurrence relation for Jacobsthal-Lucas numbers is, $\mathrm{𝐽_𝑛}$ = ...
Read MoreIncrement a number by 1 by manipulating the bits
Bit manipulation applies logical operations on a bit stream using bitwise operators like AND(&), OR(|), NOT(~), XOR(^), Left Shift() to get a required result. Using bitwise operators is beneficial as we can manipulate individual bits and they are faster than other operators. Problem Statement Given a number. Increment or add the number by 1 using bitwise operators only. (Don’t use arithmetic operators like ‘+’ , ‘-’, ‘*’ or’/’ ) Approach 1: Using One’s Complement / NOT Operator Bitwise complement / One’s complement is implemented using the NOT(~) Operator. For a number n, a bitwise complement of n i.e. ~n = ...
Read MoreSum of Fourth Powers of first N natural numbers
The fourth power of a number x is x raised to the power 4 or x4. Natural numbers are all positive integers excluding zero. Thus, the sum of the fourth powers of the first N natural numbers is − $\mathrm{Sum = 1^4 + 2^4 + 3^4 + 4^4 + … + N^4}$ This article describes some approaches for finding the sum using minimum time and space complexity. Problem Statement Given the number N, find the sum $\mathrm{1^4 + 2^4 + 3^4 + 4^4 + … + N^4}$. Example 1 Input: 3 Output: 98 Explanation $\mathrm{Sum = 1^4 + ...
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