Dining-Philosophers

The Classic Dining Philosophers Problem The Dining Philosophers problem is one of the most famous concurrency problems, introduced by Edsger Dijkstra in 1965. It beautifully illustrates the challenges of resource sharing and deadlock in concurrent systems. The Setup: Five philosophers sit around a circular table. Between each pair of philosophers is a single fork (5 forks total). Each philosopher needs two forks to eat - one from their left and one from their right. ...

The Elegant Solution In the previous articles, we explored the deadlock problem and the waiter solution. Now we’ll see the most elegant solution: the Asymmetric Solution, also known as Resource Ordering. The Key Insight: Deadlock requires circular wait. Break the circle, prevent the deadlock. The Asymmetric Solution Explained Instead of all philosophers picking up forks in the same order (left then right), we make ONE philosopher do the opposite: Philosophers 0-3: Pick up left fork first, then right fork Philosopher 4: Pick up right fork first, then left fork This simple change breaks the circular dependency and prevents deadlock! ...

Breaking the Deadlock In the previous article, we saw how the naive implementation of the Dining Philosophers problem inevitably leads to deadlock. Now we’ll implement the Waiter Solution - a centralized coordinator that prevents deadlock by controlling resource access. The Waiter Solution Concept The Idea: Add a waiter who controls access to the forks. No philosopher can pick up forks without the waiter’s permission. The waiter ensures that at most 4 philosophers can attempt to pick up forks simultaneously. ...