不到一百行python代码简单实现A星算法

最新推荐文章于 2024-04-14 22:00:38 发布

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最新推荐文章于 2024-04-14 22:00:38 发布

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文章标签： A星算法 python

本文链接：https://blog.youkuaiyun.com/weixin_45452206/article/details/99626048

为了更好地理解A星算法，自己手撸了一段91行的代码来实现A星算法
可能代码风格不是很好，因为这也就是一上午写出来的，只是简单实现了A星
过两天准备好好改动一下代码使其更易读，再好好备注一下。
#python3.7.3

import numpy as np
#设置地图和障碍，障碍物为1
tarmap=np.zeros((24,24))
tarmap.astype(np.int32)
tarmap[2][0:5]=1
tarmap[0:5,6]=1
tarmap[5,3:10]=1
tarmap[7,1:20]=1
def showMap(tarmap):#打印地图
    for i in tarmap:
        print(i)
showMap(tarmap)
class node:#每一个节点的初始化，有一个打印节点坐标和F值的方法
    def __init__(self,point,end,father=None):
        self.x=point[0]
        self.y=point[1]
        self.father=father
        if father==None:
            self.G=None
            self.H=None
            self.F=None
        else:
            self.G=(10 if abs(father.x-self.x)+abs(father.y-self.y)==1 else 14)
            self.H=abs(end[0]-self.x)*10+abs(end[1]-self.y)*10
            self.F=self.G+self.H
    def show(self):
        print([self.x,self.y],self.F)
openlist=[]
closelist=[]
start=[0,0]
end=[23,23]
def findMinF(openlist):#在openlist中找到最小F的节点
    minF=999999999
    minIndex=0
    for i,j in enumerate(openlist):
        if j.F==None:
            continue
        if j.F<minF:
            minF,minIndex=j.F,i
    return openlist[minIndex]
def nodeIn(point,openlist):#查看节点是否在openlist中
    for i in openlist:
        if point.x==i.x and point.y==i.y:
            return i
    return False
def listAppend(point,openlist,tarmap):#将当前节点的邻近节点更新并加入到openlist中
    points=[]
    temp=[-1,0,1]
    for i in temp:
        for j in temp:
            points.append([point.x+i,point.y+j])
    points.pop(4)
    for i in points:
        if 23>=i[0]>=0 and 23>=i[1]>=0:
            t=node(i,end,point)
            t1=nodeIn(t,openlist)
            t2=nodeIn(t,closelist)
            if tarmap[i[0],i[1]]==1 or t2 is not False:
                continue
            if t1 and t1.G>t.G:
                openlist.remove(t1)
                openlist.append(t)
            if t1 is False:
                openlist.append(t)
def getres(res,tarmap):#从终点找到来时的路径并将路径画到原来的地图上
    reslist=[]
    cur=res
    while [cur.x,cur.y]!=start:
        reslist.append([cur.x,cur.y])
        cur=cur.father
    reslist.append([cur.x,cur.y])
    for i in reslist:
        tarmap[i[0],i[1]]=2
    showMap(tarmap)
    return reslist
#实际操作
openlist.append(node(start,end))
while openlist!=[] or nodeIn(node(end,end),closelist) is False:
    temp=findMinF(openlist)
    openlist.remove(temp)
    closelist.append(temp)
    listAppend(temp,openlist,tarmap)
print('-----------------------------')
res=nodeIn(node(end,end),closelist)
reslist=getres(res,tarmap)