When using Kahn's Algorithm for topological sorting, there are some common mistakes that can mess things up or make the process slow. Here are the main mistakes to watch out for:

1. Not Checking the Input Graph:

   • If you don’t check for cycles in the graph, you might end up with problems. Kahn’s Algorithm works best with something called a Directed Acyclic Graph (DAG). Checking for cycles might seem tricky, but it’s really important. You can use a method called DFS to make sure there are no cycles before you start.

2. Messing Up Node Dependencies:

   • If you don’t keep track of how many connections each node has, you might skip over some nodes or process them more than once. It’s really important to correctly count how many connections (in-degrees) each node has. Use a good tool, like a priority queue, to help you keep track of these counts efficiently.

3. Picking Poor Data Structures:

   • Using slow data structures, like regular arrays, for queue tasks can make things run slower. Instead, try using a priority queue or a deque. These options allow you to add and remove nodes quickly, which is key to keeping everything running smoothly.

4. Forgetting Edge Cases:

   • Edge cases are special situations, like graphs with only one node or fully connected parts, which can give unexpected results if you don’t plan for them. Always test your algorithm with different types of graphs to catch these issues.

5. Not Checking the Output:

   • If you don’t check if your result is a valid topological sort, you might miss something important. After running your algorithm, compare the output to the original graph to make sure all the connections between nodes are still correct.

By knowing these common issues and using the right checks and data structures, you can make your version of Kahn's Algorithm more reliable and faster. This will help you get the right topological sorting results, even for tricky graphs.