Implement Layer History and Grid Counting

The coding portion covered two independent tasks. 1. Implement a simplified layer editor for a design tool. The editor maintains an ordered list of layer IDs. Support the following operations: - `addLayer(id, index)`: insert a new layer at the given position. - `removeLayer(id)`: remove an existing layer. - `moveLayer(id, newIndex)`: move a layer to a new position. - `undo()`: revert the most recent committed edit. - `redo()`: re-apply the most recently undone edit. - `beginBatch()` and `endBatch()`: all edits inside a batch must be treated as one atomic history entry. Assume batches are not nested. If a new edit is applied after an `undo()`, the redo history must be cleared. `undo()` and `redo()` must restore the exact previous layer ordering. 2. Given a 2D grid containing `L` for land and `W` for water, count how many connected land regions exist. Two land cells belong to the same region if they share a side. Write an algorithm and analyze its time and space complexity.