public KD_Node Make_KD_Tree(List <Point> points, int topLeftX, int topLeftY, int bottomRightX, int bottomRightY, Axis axis)
{
if (points.Count <= 1)
{
return(new KD_Node {
ThePoint = points.FirstOrDefault(), TopLeftX = topLeftX, TopLeftY = topLeftY, BottomRightX = bottomRightX, BottomRightY = bottomRightY, IsLeaf = true
});
}
else
{
KD_Node TreeNode = new KD_Node()
{
TopLeftX = topLeftX, TopLeftY = topLeftY, BottomRightX = bottomRightX, BottomRightY = bottomRightY, IsLeaf = false
};;
List <Point> orderPoints;
if (axis == Axis.X)
{
orderPoints = points.OrderBy(p => p.X).ToList();
}
else
{
orderPoints = points.OrderBy(p => p.Y).ToList();
}
/////////////////////////////////////
int pLength = points.Count();
List <Point> leftOrderPoints = new List <Point>();
List <Point> rightOrderPoints = new List <Point>();
int c = 0;
while (c < pLength / 2)
{
leftOrderPoints.Add(orderPoints[c]);
c++;
}
while (c < pLength)
{
rightOrderPoints.Add(orderPoints[c]);
c++;
}
//////////////////////////////////
if (axis == Axis.X)
{
TreeNode.LeftSubTree = Make_KD_Tree(leftOrderPoints, topLeftX, topLeftY, leftOrderPoints.Last().X, bottomRightY, Axis.Y);
TreeNode.RightSubTree = Make_KD_Tree(rightOrderPoints, rightOrderPoints.First().X, topLeftY, bottomRightX, bottomRightY, Axis.Y);
}
else
{
TreeNode.LeftSubTree = Make_KD_Tree(leftOrderPoints, topLeftX, topLeftY, bottomRightX, rightOrderPoints.Last().Y, Axis.X);
TreeNode.RightSubTree = Make_KD_Tree(rightOrderPoints, topLeftX, rightOrderPoints.First().Y, bottomRightX, bottomRightY, Axis.X);
}
return(TreeNode);
}
}
public List <Point> Search_KD_Tree(KD_Node root, int topLeftX, int topLeftY, int bottomRightX, int bottomRightY)
{
var tmpList = new List <Point>();
if (true == root.IsLeaf)
{
if (topLeftX <= root.ThePoint.X && topLeftY <= root.ThePoint.Y && root.ThePoint.X <= bottomRightX && root.ThePoint.Y <= bottomRightY)
{
tmpList.Add(root.ThePoint);
}
}
else
{
if (root.LeftSubTree.TopLeftX < bottomRightX && root.LeftSubTree.BottomRightX > topLeftX &&
root.LeftSubTree.TopLeftY < bottomRightY && root.LeftSubTree.BottomRightY > topLeftY)
{
tmpList.AddRange(
Search_KD_Tree(root.LeftSubTree,
Math.Max(root.LeftSubTree.TopLeftX, topLeftX),
Math.Max(root.LeftSubTree.TopLeftY, topLeftY),
Math.Min(root.LeftSubTree.BottomRightX, bottomRightX),
Math.Min(root.LeftSubTree.BottomRightY, bottomRightY))
);
}
if (root.RightSubTree.TopLeftX < bottomRightX && root.RightSubTree.BottomRightX > topLeftX &&
root.RightSubTree.TopLeftY < bottomRightY && root.RightSubTree.BottomRightY > topLeftY)
{
tmpList.AddRange(
Search_KD_Tree(root.RightSubTree,
Math.Max(root.RightSubTree.TopLeftX, topLeftX),
Math.Max(root.RightSubTree.TopLeftY, topLeftY),
Math.Min(root.RightSubTree.BottomRightX, bottomRightX),
Math.Min(root.RightSubTree.BottomRightY, bottomRightY))
);
}
}
return(tmpList);
}
