public int CountShips(Sea sea, int[] topRight, int[] bottomLeft)
{
// Divide and Conquer.
if (!sea.HasShips(topRight, bottomLeft))
{
return(0);
}
if (topRight[0] == bottomLeft[0] && topRight[1] == bottomLeft[1])
{
return(1);
}
if (topRight[0] > bottomLeft[0])
{
// Divide into left and right parts.
int mid = bottomLeft[0] + (topRight[0] - bottomLeft[0]) / 2;
int left = CountShips(sea, new int[] { mid, topRight[1] }, bottomLeft);
int right = CountShips(sea, topRight, new int[] { mid + 1, bottomLeft[1] });
return(left + right);
}
else
{
// Divide into bottom and top parts.
int mid = bottomLeft[1] + (topRight[1] - bottomLeft[1]) / 2;
int bottom = CountShips(sea, new int[] { topRight[0], mid }, bottomLeft);
int top = CountShips(sea, topRight, new int[] { bottomLeft[0], mid + 1 });
return(bottom + top);
}
}
public int CountShips(Sea sea, int[] rt, int[] lb)
{
int l = lb[0];
int b = lb[1];
int r = rt[0];
int t = rt[1];
if (!sea.HasShips(rt, lb))
{
return(0);
}
if (l == r && b == t)
{
return(1);
}
int x = l + (r - l) / 2;
int y = b + (t - b) / 2;
return
(CountShips(sea, new int[] { r, t }, new int[] { x + 1, y + 1 }) +
CountShips(sea, new int[] { x, t }, new int[] { l, y + 1 }) +
CountShips(sea, new int[] { x, y }, new int[] { l, b }) +
CountShips(sea, new int[] { r, y }, new int[] { x + 1, b }));
}