Players move right along a line toward an endpoint while a watcher freezes any player in its line of sight and flips direction at given times. How many players reach the end by time T?

Watcher Simulation: players start at given positions on a line and move right one unit per time step toward endpoint L. A watcher starts at position W, moves at the same speed in the direction it faces and flips direction at the given (possibly unsorted) timestamps. Any player in the watcher's line of sight stays frozen; a player at exactly the watcher's position may still move. Return how many players reach L by time T. Example: T=2, players=[1,4], W=3, L=5, flips=[1] gives 1.