Count players reaching end with moving watchers

You are given a 1D line of **L** cells indexed **0..L-1**. The **end cell** is **L-1**. There are: - **W watchers** with initial integer positions `watchers[]`. - **P players** with initial integer positions `players[]`. - A time horizon **T** (non-negative integer, number of unit-time steps). - An unsorted list `flipTimes[]` of integer timestamps. **At each timestamp `t` in `flipTimes`, all watchers reverse direction**. Movement model (discrete time): - Time steps are `t = 0, 1, ..., T-1`. - Each watcher has a facing direction (`LEFT` or `RIGHT`). **All watchers start facing LEFT at time 0**. - At the **start** of each step `t`, if `t` is in `flipTimes`, all watchers reverse direction. - **Watching rule:** At step `t`, a watcher at position `x`: - if facing `LEFT`, watches **all cells `< x`**; - if facing `RIGHT`, watches **all cells `> x`**. A player is considered **watched** if at least one watcher watches the player’s current cell. - **Player move:** During step `t`, each player tries to move **one cell to the right** (from `p` to `min(p+1, L-1)`), **but if the player is watched at the start of the step, the player cannot move and stays in place**. - **Watcher move:** After all players have (attempted) to move, each watcher moves one cell in its facing direction: - `LEFT`: `x = max(x-1, 0)` - `RIGHT`: `x = min(x+1, L-1)` Task: - After performing exactly **T** steps, return **how many players are at cell `L-1`**. Notes / clarifications: - Multiple players and watchers may occupy the same cell. - `flipTimes[]` may contain duplicates and is not sorted. Write a function that takes `(L, watchers, players, T, flipTimes)` and returns the count. Suggested constraints (for implementation): - `1 <= L <= 2e5` - `0 <= W, P <= 2e5` - `0 <= T <= 2e5` - `0 <= flipTimes[i] <= T-1`