QHYun_practice-17-A*算法

算法的java实现

package AStarAlgo;
 
import java.util.ArrayList;
import java.util.List;
 
/**
 * <p> TODU </P>
 *
 * @author yeager
 * @Version V1.1.1.0
 * @date 2023/11/24 13:48
 */
public class AStarFindpathAlgo {
    int Width = 20;
    int Height = 20;
    APoint startPoint = null;
    APoint endPoint = null;
    APoint minPoint = null;
    APoint nowPoint = null;
    List<APoint> OpenPts = new ArrayList<APoint>();
    List<APoint> SurrondPts = new ArrayList<APoint>();
    List<APoint> ClosePts = new ArrayList<APoint>();
    List<APoint> WallPts = new ArrayList<APoint>();
 
    public static void main (String[] args)
    {
        System.out.println("now we start!");
        AStarFindpathAlgo algo = new AStarFindpathAlgo();
        //初始化地图
        //假设一个初始化
        //开始点
        algo.startPoint = new APoint();
        algo.startPoint.x = 2;
        algo.startPoint.y = 2;
 
        //结束点
        algo.endPoint = new APoint();
        algo.endPoint.x = 6;
        algo.endPoint.y = 2;
 
        //设置墙
        algo.WallPts.add(new APoint(4,1));
        algo.WallPts.add(new APoint(4,2));
        algo.WallPts.add(new APoint(4,3));
 
        for(int i = 0; i < algo.WallPts.size(); i ++)
        {
            algo.ClosePts.add(algo.WallPts.get(i));
        }
 
        //开始执行算法
        algo.excuteAlgo();
    }
 
 
 
    public AStarFindpathAlgo()
    {
 
    }
 
    public  void excuteAlgo()
    {
        System.out.println("now we start!");
        //找到开始点的周边点，作为出发，设置基本信息，作为第一轮
        findStartSurround(startPoint);
        //将起始点加入关列表
        ClosePts.add(startPoint);
 
        //找到开列表中 F最小的值
        while(true)
        {
            minPoint = findMinPt();
            System.out.println("minPt:" +minPoint.x +", "+ minPoint.y );
 
            removeFromOpenPts(minPoint);
            nowPoint = minPoint;
            ClosePts.add(minPoint);
            finMinSurrond(minPoint);
            refreshGValue(nowPoint);
            if(OpenPts.size() <= 0 || findInOpenPts(endPoint))
                break;
        }
    }
 
    public void refreshGValue(APoint pt)
    {
        for(int i = 0 ; i < SurrondPts.size(); i++)
        {
            APoint surPt = SurrondPts.get(i);
            if(findInOpenPts(surPt))
            {
                surPt.new_G = surPt.Sconst + pt.old_G ;
                if(surPt.new_G < surPt.old_G)
                {
                    surPt.father = pt;
                    surPt.old_G = surPt.new_G ;
                    surPt.G = surPt.new_G;
                    surPt.F = surPt.G +surPt.H;
                }
            }
            else
            {
                surPt.new_G = pt.G + surPt.Sconst;
                surPt.father = pt;
                surPt.old_G = surPt.new_G ;
                surPt.G = surPt.new_G;
                surPt.H = 10*(Math.abs(surPt.x - endPoint.x)+ Math.abs(surPt.y - endPoint.y));
                surPt.F = surPt.G +surPt.H;
                OpenPts.add(surPt);
                System.out.println("计算值：("+ surPt.x +","+surPt.y +")[father:("+surPt.father.x+ ","+ surPt.father.y +")]");
                System.out.println("F:G:h---"+surPt.F+":"+surPt.G+":"+surPt.H);
            }
 
        }
    }
 
    public boolean findInOpenPts(APoint pt)
    {
        for(int i = 0; i < OpenPts.size();i++ )
        {
            if(pt.x == OpenPts.get(i).x &&pt.y == OpenPts.get(i).y)
            {
                return true;
            }
        }
        return false;
    }
    public void removeFromOpenPts(APoint pt)
    {
        for(int i = 0; i < OpenPts.size();i++ )
        {
            if(pt.x == OpenPts.get(i).x &&pt.y == OpenPts.get(i).y)
            {
                OpenPts.remove(i);
            }
        }
    }
    public APoint findMinPt()
    {
        APoint minPoint = OpenPts.get(0);
        for(int i = 1; i < OpenPts.size();i++)
        {
            if(minPoint.F >  OpenPts.get(i).F)
            {
                minPoint = OpenPts.get(i);
            }
        }
        return minPoint;
 
    }
 
    public void findStartSurround(APoint sPt)
    {
        SurrondPts.clear();
        for(int i = -1; i < 2; i++)
        {
            for(int j = -1; j < 2; j++)
            {
                if(i ==0 && j ==0)
                    continue;
                int sconst = 10;
                if(Math.abs(i) == 1 &&Math.abs(j) == 1)
                    sconst = 14;
 
                APoint pt = new APoint(sPt.x +i,sPt.y + j);
                //判断一下是否超越了地图边界
                if(pt.x < 0 || pt.y < 0 || pt.x >= Width || pt.y >= Height)
                {
                    continue;
                }
                //判断一下是不是关闭列表的点
                if(isInClosePt(pt))
                {
                    continue;
                }
                pt.new_G = sconst;
                pt.old_G =sconst;
                pt.G = sconst;
                pt.H = 10*(Math.abs(pt.x - endPoint.x)+ Math.abs(pt.y - endPoint.y));
                pt.F = pt.G +pt.H;
                pt.father = sPt;
                System.out.println("计算值：("+ pt.x +","+pt.y +")[father:("+pt.father.x+ ","+ pt.father.y +")]");
                System.out.println("F:G:h---"+pt.F+":"+pt.G+":"+pt.H);
                SurrondPts.add(pt);
                OpenPts.add(pt);
            }
        }
    }
 
    public void finMinSurrond(APoint sPt)
    {
        SurrondPts.clear();
        for(int i = -1; i < 2; i++)
        {
            for(int j = -1; j < 2; j++)
            {
                if(i ==0 && j ==0)
                    continue;
 
                APoint pt = new APoint(sPt.x +i,sPt.y + j);
 
                //判断一下是否超越了地图边界
                if(pt.x < 0 || pt.y < 0 || pt.x >= Width || pt.y >= Height)
                {
                    continue;
                }
                //判断一下是不是关闭列表的点
                if(isInClosePt(pt))
                {
                    continue;
                }
                if(Math.abs(i) == 1 &&Math.abs(j) == 1)
                    pt.Sconst = 14;
                SurrondPts.add(pt);
            }
        }
 
    }
    public boolean isInClosePt(APoint pt)
    {
        boolean find = false;
        for(int i = 0; i <ClosePts.size(); i++)
        {
            if(pt.x == ClosePts.get(i).x && pt.y == ClosePts.get(i).y)
            {
                find = true;
            }
        }
        return find;
    }
 
}