DSA

Data structure & algorithm using swift language.

Count all prime numbers

[Question] Count all prime numbers from given nExample Input: n = 10Output: 4Explanation: There are 4 prime numbers less than 10, they are 2, 3, 5, 7.Solution: using Sieve of Eratosthenes AlgoThe Sieve of Eratosthenes is an ancient and efficient algorithm for finding all prime numbers up to a specified integer \( n \). It …

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Logarithms Explained

In this article I will explain about how log values is being calculated Remember Log 2 8 = 3 which means 2 3 = 8 Example 2 Log 10 1000 = 4 which means 10 4 = 10,000

How to generate parentheses

[Question]: Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.Example: – n = 2. —   [“(())”, “()()”] Approach: We can solve using backtracking / recursion

How to Remove all occurrence of certain number ?

[Question]: Given an integer array nums and an integer k, remove all occurrences of k in nums in-place. The order of the elements may be changed. Then return the count after removal Approach: We can declare a variable which holds index initial it’s 0 now move elements which are not matched with k

How to rotate linked list with K-th places ?

[Question]: Given the head of a linked list, rotate the list to the right by k places.Example: – Input: head = [1,2,3,4,5], k = 2 Output: [4,5,1,2,3] #Approach Step: 1 Create tail node which moves till endsStep: 2 Create curr the tail node is the (len-k)-th node (1st node is head)Step: 3 Reorder linked list