Hi,
I am new to Java coding (familiar with simple C++ though) and don't have a Java compiler. Tried looking for one but it there doesn't sem to be a visuall C++ type compiler for Java, i.e. I couldn't find one that seemed easy to use.
Could you guys check this function for me and tell me if I've done anything wrong or very innefficient please?
I am NOT allowed to use libraries or anything but the basic datatypes...
Code:static int[] speedroute( boolean speedmap[][] , int cx , int cy , int dx , int dy )
{
/* My code begins here. */
int route[] = null;
/* Using "A star" algorithm to find shortest path. Assuming we cannot move diagonally.
Using the Manhattan heuristic method to estimate shortest path length */
int maxx=128;
int maxy=128;
int listdepth = 4; /* {list?, parent x, parent y, g} */
int open[][][] = new int[maxx][maxy][listdepth];
int closed[][][] = new int[maxx][maxy][listdepth];
open[cx][cy] = {1,cx,cy,0};
int isfirststep=1;
int ex=cx; int ey=cy;
int lowestopenf=maxx+maxy;
int neighbours[][] = new int[4][2];
for(;;)
{
for(int i=0;i<maxx;i++)
{
for(int j=0;<maxy;j++)
{
if(open[i][j][0]&&(abs(i-dx)+abs(j-dy)+open[open[i][j][1]][open[i][j][2]][3]+1)<lowestopenf)
{
ex=i; ey=j;
}
}
}
if(lowestopenf==maxx+maxy)
{
return route;
}
else if(ex==dx&&ey==dy)
{
break;
}
else
{
open[ex][ey][0]=0;
closed[ex][ey]={1,open[ex][ey][1],open[ex][ey][2],open[open[ex][ey][1]][open[ex][ey][2]][3]+1)};
neighbours={{ex,ey+1},{ex+1,ey},{ex,ey-1},{ex-1,ey}};
for(int i=0;i<4;i++)
{
if(neighbours[i][0]<maxx&&neighbours[i][0]>=0
&&neighbours[i][1]<maxy&&neighbours[i][1]>=0
&&!speedmap[neighbours[i][0]][neighbours[i][1]])
{
if(closed[neighbours[i][0]][neighbours[i][1]][0]&&
closed[ex][ey][3]+1<closed[neighbours[i][0]][neighbours[i][1]][1])
{
closed[neighbours[i][0]][neighbours[i][1]][3]
=closed[ex][ey][3]+1;
closed[neighbours[i][0]][neighbours[i][1]][1]=ex;
closed[neighbours[i][0]][neighbours[i][1]][2]=ey;
open[neighbours[i][0]][neighbours[i][1][3]]
=open[ex][ey][3]+1;
open[neighbours[i][0]][neighbours[i][1]][1]=ex;
open[neighbours[i][0]][neighbours[i][1]][2]=ey;
}
else if(open[neighbours[i][0]][neighbours[i][1]][0]&&
open[ex][ey][3]+1<open[neighbours[i][0]][neighbours[i][1]][1])
{
open[neighbours[i][0]][neighbours[i][1][3]]
=open[ex][ey][3]+1;
open[neighbours[i][0]][neighbours[i][1]][1]=ex;
open[neighbours[i][0]][neighbours[i][1]][2]=ey;
closed[neighbours[i][0]][neighbours[i][1]][3]
=closed[ex][ey][3]+1;
closed[neighbours[i][0]][neighbours[i][1]][1]=ex;
closed[neighbours[i][0]][neighbours[i][1]][2]=ey;
}
else
{
open[neighbours[i][0]][neighbours[i][1]]={1,ex,ey,open[ex][ey][3]+1};
}
}
}
}
}
/* Having found the shortest path we now follow the trail of parent squares starting from
the target square until we get to the element who's parent square is the starting square.*/
int step[] = {dx,dy};
for(int i=0;i<maxx+maxy;i++)
{
if(open[step[0]][step[1]][1]==cx&&open[step[0]][step[1]][2]==cy)
{
nextstep={step[0]+1,step[1]+1};
break;
}
else
{
step[0]=open[step[0]][step[1]][1]; step[1]=open[step[0]][step[1]][2];
}
}
/* My code ends here */
return nextstep;
}
