Q$1$: $(6$ pts$)$ Concurrent programs may require all processes to begin executing a piece of code at the same tim processes that first arrive at a point in the code $($rendez$-$vous point$)$ are waiting for all the rest. When all of the have come to that point, then the execution of each one continues from the next command. The synchronizati pattern implementing this requirement is called "barrier". Provide code that implements the barrier for N process using semaphores and a common variable.

mutex $=$ semaphore