A*算法的实现

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<list>
#include<string>
#include<ctime>
#include <algorithm>
#include"jsoncpp/json.h"
using namespace std;
const int n=5;
const int dx[4]={-1,0,1,0};     //up,right,down,left
const int dy[4]={0,1,0,-1};
int invalid[n][n]={
0,1,0,1,0,
0,0,0,1,0,
0,0,0,1,0,
0,1,0,0,0,
0,1,0,1,0
};
int tx=4,ty=0,tx1=4,ty1=4;

struct point
{
    int f,g,h;
    int x,y;
    point(int _x=0,int _y=0)
    {
        x=_x;
        y=_y;
    }
};

list<point> CloseList;
list<point> OpenList;
point father[100][100];    //记录路径 


bool My_validDirection1(int x,int y)  //判断当前移动方向的下一格是否合法
{
    if (x>=n || y>=n || x<0 || y<0) return false;
    if (invalid[x][y]) return false;
    return true;
}


int As()
{
    point start(tx,ty);
    point end(tx1,ty1);
    point tempStart(0,0);    //当前点 
    
    OpenList.push_front(start);
    while(OpenList.size()!=0)
    {
        //选出f最小点作为当前点 
        list<point>::iterator it_close=OpenList.begin();
        list<point>::iterator it=OpenList.begin();
        tempStart=*it;
        ++it;
        for(;it!=OpenList.end();++it)
        {
            if((*it).f<tempStart.f)
            {
                tempStart=*it;
                it_close=it;
            }
        }
        //将当前点加入关闭列表 
        OpenList.erase(it_close);
        CloseList.push_front(tempStart);
        //周围的点进行扩展 
        for(int i=0;i<4;++i)
        {
            int exist=0,close=0;
            point p(tempStart.x+dx[i],tempStart.y+dy[i]);
            //如果已经存在关闭列表，则不进行操作 
            for(it=CloseList.begin();it!=CloseList.end();++it)
            {
                if((*it).x==p.x&&(*it).y==p.y)
                {
                    close=1;
                    break;
                }
            }                    
            //如果是非法点或者存在于关闭列表，则不操作 
            if(My_validDirection1(p.x,p.y)&&!close)
            {
                for(it=OpenList.begin();it!=OpenList.end();++it)
                {
                    if((*it).x==p.x&&(*it).y==p.y)
                    {
                        exist=1;
                        break;
                    }
                }        
                //如果存在于开启列表，则更新fg        
                if(exist)
                {
                    int g=tempStart.g+1;
                    if(g>p.g)
                    {
                        tempStart=point(father[tempStart.x][tempStart.y].x,father[tempStart.x][tempStart.y].y);
                        p.g=abs(p.x-tempStart.x)+abs(p.y-tempStart.y);
                        p.f=p.g+p.h;
                    }
                }
                //否则加入开启列表，计算fgh 
                else
                {
                    p.g=abs(p.x-tempStart.x)+abs(p.y-tempStart.y);
                    p.h=abs(p.x-tx1)+abs(p.y-ty1);
                    p.f=p.g+p.h;
                    OpenList.push_front(p);
                    father[p.x][p.y]=tempStart;
                }
            }
        }
        //查询目标点是否在开启列表内 
        for(it=OpenList.begin();it!=OpenList.end();++it)
        {
            if((*it).x==tx1&&(*it).y==ty1)
            {
                int a=tx1,b=ty1,xx=tx1,yy=ty1;
                while(father[xx][yy].x!=tx||father[xx][yy].y!=ty)
                {
                    cout<<xx<<","<<yy<<"<-"    ;            
                    a=father[xx][yy].x;
                    b=father[xx][yy].y;
                    xx=a;yy=b;
                }
                cout<<xx<<","<<yy<<"<-start";
                if(xx==tx)
                {
                    if(yy>ty)
                    {//r2
                        return 1;
                    }
                    else
                    {//l0
                        return 3;
                    }
                }
                else
                {
                    if(xx>tx)
                    {//d1
                        return 2;
                    }
                    else
                    {//u3
                        return 0;
                    }                    
                }
            }
        }            
        
    }
    return -1;
}
//0:left,1:down,2:right,3:up

int main()
{

    int ans=As();

//    cout<<ans<<endl;
 
    return 0;
}