AI-路径导航（最短路径算法 and A算法）

#include <cstdio>//with this method,we can find all the shortest ways from the start point to any other points.
#include <iostream>
#include <algorithm>
#include <fstream>
#include <string>
#include <sstream>
#include <cmath>
#include <set>
#include <cstring>
using namespace std;//the problem of this shortest-path method is that you must find the best way of every other point.Tihs will be very complex when the amount of points increase.
#define N 13
#define BG 1100000000
double pmap

;//point map

char sp,tp;
int sn,tn;

struct point{
int num;
double dist;
int pnum;
bool operator < (const point &a)const
{
return a.dist>dist;//order the set by dist
}
};

multiset<point>qo;//balace tree~,every time we should find the point wihch is closest to the start point quickly.
multiset<point>qc;//to find the whole
multiset<point>::iterator it;
point inp,outp;
double d
;
int p
;//p
stores the best parent of every point

void input()//the format of the first 8 lines is"cityname x y",and the following lines are the cities which are connected.
{
cin>>sp>>tp;

ifstream OpenFile("/Users/liuyuhan/Desktop/Blue_Home/MyTest/AMusic/LineLandMail/CityPoints.txt");
string ch;
int cityx
,cityy
;
int i;
while(!OpenFile.eof())
{
int hl,vl;
char city;
int x,y;
char Xcity,Ycity;
getline(OpenFile,ch);
stringstream seg;
seg.str(ch);
if(i<N)
{

seg>>city;
seg>>x;
seg>>y;
cityx[city-'A']=x;//the horizen index of the city
cityy[city-'A']=y;//the vertical index of the city
}
else
{
//int x,y;
seg>>Xcity;
seg>>Ycity;
x=Xcity-'A';//the one city
y=Ycity-'A';//the other city
hl=abs(cityx[x]-cityx[y]);//horizen length
vl=abs(cityy[x]-cityy[y]);
pmap[x][y]=sqrt((double)(hl*hl+vl*vl));
pmap[y][x]=pmap[x][y];
}
i++;

}
OpenFile.close();
}

void print_out()
{
char pc
;
int i=0;
pc[0]=tp;
int a=p[tn];
while(a!=-1)
{
pc[++i]=a+'A';
a=p[a];
}
i++;
while(i--)
{
if(i>0)
printf("%c->",pc[i]);
else
printf("%c\n",tp);
}
printf("%0.4f",d[tn]);
//cout<<endl;
}

void solve(int s,int t)
{
inp.num=s;
inp.dist=0;
inp.pnum=-1;
qo.insert(inp);
it=qo.begin();
int i;

while(it->num!=t)
{
outp=*it;
qc.insert(outp);
qo.erase(it);
for(i=0;i<N;i++)
if(pmap[outp.num][i]!=0&&i!=outp.pnum)//the point can be expanded
{
inp.num=i;
inp.dist=outp.dist+pmap[outp.num][i];
inp.pnum=outp.num;
if(d[inp.num]>inp.dist)
{
d[inp.num]=inp.dist;
p[inp.num]=outp.num;
}
qo.insert(inp);
}
it=qo.begin();
}
print_out();
}
int main()
{
input();
sn=sp-'A';
tn=tp-'A';
for(int i=0;i<N;i++)
d[i]=BG;
d[sn]=0;
p[sn]=-1;
solve(sn,tn);

}

#include <cstdio>//with this method,we can find all the shortest ways from the start point to any other points.
#include <iostream>
#include <algorithm>
#include <fstream>
#include <string>
#include <sstream>
#include <cmath>
#include <set>
#include <cstring>
using namespace std;
#define N 13//there are 13 cities,and it can be more in fact.
#define BG 1100000000
double pmap

;//point map

char sp,tp;
int sn,tn;

struct point{
int num;
double gdis;
double fdis;
int pnum;
bool operator < (const point &a)const
{
return a.fdis>fdis;//order the set by fdis(fdis=g[num]+h[num])
}
};

multiset<point>qo;//balace tree~,every time we should find the point wihch is closest to the start point quickly.
multiset<point>qc;//to find the whole
multiset<point>::iterator it;
point inp,outp;
double d
;
int p
;//p
stores the best parent of every point
int cityx
,cityy
;
double h
;//that's the straight diastance from i to t

void input()//the format of the first 8 lines is"cityname x y",and the following lines are the cities which are connected.
{
cin>>sp>>tp;

ifstream OpenFile("/Users/liuyuhan/Desktop/Blue_Home/MyTest/AMusic/LineLandMail/CityPoints.txt");
string ch;

int i;
while(!OpenFile.eof())
{
int hl,vl;
char city;
int x,y;
char Xcity,Ycity;
getline(OpenFile,ch);
stringstream seg;
seg.str(ch);
if(i<N)
{

seg>>city;
seg>>x;
seg>>y;
cityx[city-'A']=x;//the horizen index of the city
cityy[city-'A']=y;//the vertical index of the city
}
else
{
//int x,y;
seg>>Xcity;
seg>>Ycity;
x=Xcity-'A';//the one city
y=Ycity-'A';//the other city
hl=abs(cityx[x]-cityx[y]);//horizen length
vl=abs(cityy[x]-cityy[y]);
pmap[x][y]=sqrt((double)(hl*hl+vl*vl));
pmap[y][x]=pmap[x][y];
}
i++;

}
OpenFile.close();
}

void print_out()
{
char pc
;
int i=0;
pc[0]=tp;
int a=p[tn];
while(a!=-1)
{
pc[++i]=a+'A';
a=p[a];
}
i++;
while(i--)
{
if(i>0)
printf("%c->",pc[i]);
else
printf("%c\n",tp);
}
printf("%0.4f\n",d[tn]);
//cout<<endl;
}

void solve(int s,int t)
{
inp.num=s;
inp.gdis=0;
inp.fdis=0+h[s];
inp.pnum=-1;
qo.insert(inp);
it=qo.begin();
int i;

while(it->num!=t)
{
outp=*it;
qc.insert(outp);
qo.erase(it);
for(i=0;i<N;i++)
if(pmap[outp.num][i]!=0&&i!=outp.pnum)//the point can be expanded
{
inp.num=i;
inp.gdis=outp.gdis+pmap[outp.num][i];
inp.fdis=inp.gdis+h[i];//that's the A method's important part
inp.pnum=outp.num;
if(d[inp.num]>inp.gdis)
{
d[inp.num]=inp.gdis;
p[inp.num]=outp.num;
}
qo.insert(inp);
}
it=qo.begin();
}
print_out();
}
int main()
{
input();
sn=sp-'A';
tn=tp-'A';
for(int i=0;i<N;i++)
d[i]=BG;
d[sn]=0;
p[sn]=-1;
int i;
for(i=0;i<N;i++)
{
int hx=abs(cityx[i]-cityx[tn]);
int hy=abs(cityy[i]-cityy[tn]);
h[i]=sqrt((double)(hx*hx+hy*hy));
}
solve(sn,tn);

}