public GameOfLife step() {
Set<Coordinates> newLiveCells = new HashSet<Coordinates>();
Set<Coordinates> cellsNextToALiveCell = new HashSet<Coordinates>();
for (Coordinates coordinates : liveCells) {
int numberOfNeighbors = countLiveNeighbors(coordinates);
if ((numberOfNeighbors == 2) && isCellAlive(coordinates.x, coordinates.y))
turnCellAlive(newLiveCells, coordinates);
cellsNextToALiveCell.add(new Coordinates(coordinates.x + 1, coordinates.y + 1));
cellsNextToALiveCell.add(new Coordinates(coordinates.x + 1, coordinates.y + 0));
cellsNextToALiveCell.add(new Coordinates(coordinates.x + 1, coordinates.y - 1));
cellsNextToALiveCell.add(new Coordinates(coordinates.x - 1, coordinates.y + 1));
cellsNextToALiveCell.add(new Coordinates(coordinates.x - 1, coordinates.y + 0));
cellsNextToALiveCell.add(new Coordinates(coordinates.x - 1, coordinates.y - 1));
cellsNextToALiveCell.add(new Coordinates(coordinates.x + 0, coordinates.y + 1));
cellsNextToALiveCell.add(new Coordinates(coordinates.x + 0, coordinates.y - 1));
}
for (Coordinates coordinates : cellsNextToALiveCell) {
int numberOfNeighbors = countLiveNeighbors(coordinates);
if (numberOfNeighbors == 3) turnCellAlive(newLiveCells, coordinates);
}
replaceWithContentOf(liveCells, newLiveCells);
return this;
}
public void setInitialLiveCells(long[][] initialLiveCells) {
replaceWithContentOf(this.liveCells, new HashSet<Coordinates>());
for (int i = 0; i < initialLiveCells.length; i++) {
long[] coordinates = initialLiveCells[i];
turnCellAlive(coordinates[0], coordinates[1]);
}
}
private void turnCellAlive(long x, long y) {
turnCellAlive(liveCells, new Coordinates(x, y));
}
