# Sum of all sub arrays in O(n) Time

Given an array write C# program to find the sum of all the possible sub-arrays. For.e.g. int [] a = {4, 2, 1}; Output: Possible subarrays – {4}, {2}, {1}, {4, 2}, {2, 1}, {4, 2, 1} So, sum = 4+ 2+ 1 + 6 + 3 + 7 = 23 Solution Brute force approach Problem with below program is iterating over all pairs of … Continue reading Sum of all sub arrays in O(n) Time

# Knapsack Problem

The knapsack problem is a problem in combinatorial optimization: Given a set of items, each with a weight and a value, determine the number of each item to include in a collection so that the total weight is less than or equal to a given limit and the total value is as large as possible. Given weights and values of n items, put these items … Continue reading Knapsack Problem

# Maximum sub array problem – Kadane’s Algorithm

Given a sequence of n real numbers A(1) … A(n), program to find a contiguous subarray with the largest sum For example, var arr = new int[] {-2, 1,-3, 4,-1, 2, 1,-5, 4 }; the contiguous sub array with the largest sum is [4, −1, 2, 1], with sum 6. Solution Solution via iterating over all array elements repeatedly, try each key elements Execute above … Continue reading Maximum sub array problem – Kadane’s Algorithm

# Find all sub-array from array

Question: Find all possible subarray from given array Given an array of positive integers,  Write an C# Program to find all sub arrays from an array. Answer: Subarray of an array a is a[i..j] where 0 <= i <= j < n where n is length of array. Continue reading Find all sub-array from array

# Find Pair of sum in Array.

Question Given an array of unsorted array and a number, determines all pair in array in array whose sum is equivalent to the given number For example: from provided Array “arr” find all Pair who sum is 4 Answer: Logic: Get the difference between array elements and given sum number Find the difference in reaming array to get the pairs Continue reading Find Pair of sum in Array.

# Sock Merchant – HackerRank Problem Solution

Question: John works at a clothing store. He has a large pile of socks that he must pair by color for sale. Given an array of integers representing the color of each sock, determine how many pairs of socks with matching colors there are. For example, there are n=7  socks  with colors  ar = [1,2,1,2,1,3,2]. There is one pair of color 1 and one of color 2 . There … Continue reading Sock Merchant – HackerRank Problem Solution

# Array vs ArrayList

Array: An array is a collection of similar data types that can be accessed by index. Array allocates then static memory with consecutive section of memory blocks. ArrayList: ArrayList is a collection of objects of same or different types. ArrayList size can be dynamically increased or decreased as per the requirement. Here is difference table of Array vs ArrayList Array ArrayList Array stores a fixed number of elements. ArrayList is dynamic … Continue reading Array vs ArrayList

# Convert Decimal to Binary (base -2)

Question: Write a C# program to convert any decimal number (base-10 (0 to 9)) into binary number (base-2 (0 or 1))? Answer: Decimal Number – Decimal number is a base 10 number because it ranges from 0 to 9, there are total 10 digits between 0 to 9. Any combination of digits is decimal number such as 223, 585, 192, 0, 7 etc.   Binary … Continue reading Convert Decimal to Binary (base -2)