四叉树 java 实现
此代码本是根据一个C语言写的四叉树改写的，在j2me环境下编译通过。
QuadTreeNode 类：
package QuadTreeLib; import java.util.*; /** * *
Title:
* *Description:
* *Copyright: Copyright (c) 2010
* *Company:
* * @author An Zhiqiang (Email: [email protected]) * @version 1.0 (上午11:34:06 2010) */ public class QuadTreeNode { public static final int NODE_NUMS = 4; public static final int NW = 0,NE = 1,SW = 2,SE = 3; /* * a quadrant defined below: * NW(0) | NE(1) * -----------|----------- * SW(2) | SE(3) */ public int[] rect;// x,y,w,h public Vector vec; public QuadTreeNode[] node = new QuadTreeNode[NODE_NUMS]; public QuadTreeNode(int x, int y, int w, int h) { init(x, y, w, h); } public QuadTreeNode() { } public void init(int x, int y, int w, int h) { int[] rect = new int[4]; rect[NW] = x; rect[NE] = y; rect[SW] = w; rect[SE] = h; this.rect = rect; vec = new Vector(); } public void init(int[] temprect) { this.rect = new int[4]; System.arraycopy(temprect, 0, rect, 0, 4); vec = new Vector(); } public void creatChild() { int x, y, w, h; x = rect[NW]; y = rect[NE]; w = rect[SW]; h = rect[SE]; this.node[NW] = new QuadTreeNode(x,y,w>>1,h>>1); this.node[NE] = new QuadTreeNode(x+(w>>1),y,w>>1,h>>1); this.node[SW] = new QuadTreeNode(x,y+(h>>1),w>>1,h>>1); this.node[SE] = new QuadTreeNode(x+(w>>1),y+(h>>1),w>>1,h>>1); } public boolean isHasChild(){ if(node[NW] == null){ return false; }else{ return true; } } public QuadTreeNode insertNode(QuadTree tree,int[] nodeRect,Object key){ QuadTree.debugNum++; if (Util.isInsideRect(nodeRect, rect) ) { if ( ++(tree.depth) < tree.maxDepth) { if ( !isHasChild() ) creatChild(); if (Util.isInsideRect(nodeRect, node[NE].rect) ) return node[NE].insertNode(tree, nodeRect ,key); if (Util.isInsideRect(nodeRect, node[NW].rect) ) return node[NW].insertNode(tree, nodeRect ,key); if (Util.isInsideRect(nodeRect, node[SW].rect) ) return node[SW].insertNode(tree, nodeRect ,key); if (Util.isInsideRect(nodeRect, node[SE].rect) ) return node[SE].insertNode(tree, nodeRect,key ); } /* inserts into this node since it can NOT be included in any subnodes */ addData(key); System.out.println("QuadTree.debugNum: "+ QuadTree.debugNum); return this; } return null; } public void addData(Object node_key) { if (vec == null) vec = new Vector(); vec.addElement(node_key); } /* searched tree nodes */ public void searchNodes( int[] search_box, Vector results_list) { if (Util.isOverLapped(rect, search_box)) { if (vec!=null && vec.size()>0) for (int i = 0; i < vec.size(); i++) { results_list.addElement(vec.elementAt(i)); } //list_append_node(results_list, list_node_create(current_node)); if (isHasChild()) { node[NE].searchNodes(search_box, results_list); node[NW].searchNodes(search_box, results_list); node[SW].searchNodes(search_box, results_list); node[SE].searchNodes(search_box, results_list); } } } }
Util 类：
package QuadTreeLib; /** * *
Title:
* *Description:
* *Copyright: Copyright (c) 2010
* *Company:
* * @author An Zhiqiang (Email: [email protected]) * @version 1.0 (上午11:34:35 2010) */ public class Util { /** * return true if rectA is inside rectB; * @param rectA * @param rectB */ public static boolean isInsideRect(int[] rectA,int[] rectB){ if(rectA[0]>rectB[0] && (rectA[0]+rectA[2])< (rectB[0]+rectB[2]) &&rectA[1]>rectB[1] && (rectA[1]+rectA[3])< (rectB[1]+rectB[3])){ return true; }else { return false; } } public static boolean isOverLapped(int[] rectA,int[] rectB){ if( rectA[0]+rectA[2]
QuadTree 类：
package QuadTreeLib; import java.util.*; /** * *
Title:
* *Description:
* *Copyright: Copyright (c) 2010
* *Company:
* * @author An Zhiqiang (Email: [email protected]) * @version 1.0 (上午11:34:15 2010) */ public class QuadTree { public QuadTreeNode root; public int depth; public int maxDepth; public QuadTree(int[] rect, int maxDepth) { depth = 0; this.maxDepth = maxDepth; root = new QuadTreeNode(); root.init(rect); } /* inserts a node into quadtree and return pointer to new node */ public QuadTreeNode insert(Object node_key, int[] rect) { depth = -1; debugNum = 0; return root.insertNode(this, rect, node_key); } /* searches nodes inside search_box */ void search(int[] search_box, Vector results_list) { root.searchNodes(search_box, results_list); } public static int debugNum; }