C# – Change a dictionary’s values in a foreach loop

In .NET 5 and above, you can loop through a dictionary and directly change its values. Here’s an example: This outputs the following: You couldn’t do this before .NET 5, because it would invalidate the enumerator and throw an exception: InvalidOperationException: Collection was modified; enumeration operation my not execute. Instead, you’d have to make the … Read more

HackerRank – Zig Zag Sequence solution

In this article, I’ll explain the Zig Zag Sequence algorithm problem on HackerRank. Problem statement: You’re given an integer array with an odd number of elements (ex: [5, 2, 3, 1, 4]). You need to re-arrange the elements so they’re in a zig zag sequence, which means: Here’s a diagram to help you visualize what … Read more

HackerRank – Sock Merchant solution

In this article, I’ll explain how to solve the Sock Merchant algorithm problem on HackerRank. Problem statement: You’re given an integer array and need to count the number of pairs of matching integers. The integers will be between 1 and 100. For example, [3,1,3] has one matching pair (the 3s match). Approach First, we know … Read more