Java: Randomizing the Order of Method Recursive Calls
For DFS maze generation in Java I wanna randomize the order in which the recursive calls of a DFS are made:
for (int rows=i; rows<M; rows++)
for (int cols=j; cols<N; cols++){
if(northValid)
{
DFS(iNorth,j);
}
if(southValid){
DFS(iSouth,j);
}
if(eastValid){
开发者_开发问答 DFS(i, jEast);
}
if(westValid){
DFS(i,jWest);
}
How can I do that?
Switch on a call to the Random class:
Random r = new Random();
for (int rows=i; rows<M; rows++)
for (int cols=j; cols<N; cols++) {
bool found = false;
while (!found)
switch (r.next() % 4) {
case 0: if(northValid) { DFS(iNorth,j); found = true; } break;
case 1: if(southValid) { DFS(iSouth,j); found = true; } break;
case 2: if(eastValid) { DFS(i, jEast); found = true; } break;
case 3: if(westValid) { DFS(i, jWest); found = true; } break;
}
}
Note that, using this approach, you need to loop over the switch until it hits an available wall, and then continue. It's a bit inefficient, but quite simple.
Pseudo Code:
for (int rows=i; rows<M; rows++)
{
for (int cols=j; cols<N; cols++)
{
// Generate a random number between 0 to 3 => %4
switch(randomNumber)
{
case 0: DFS(iNorth,j);
break;
// ...
case 3: DFS(i,jWest);
break;
default: break;
}
}
}
I ended up using this:
Double lottery = Math.random();
for (int rows=i; rows<M; rows++)
for (int cols=j; cols<N; cols++){
if (lottery>=0.5D){
if(northValid)
{
DFS(iNorth,j);
}
if(southValid){
DFS(iSouth,j);
}
if(eastValid){
DFS(i, jEast);
}
if(westValid){
DFS(i,jWest);
}
}
else if (lottery<0.5D)
{
if(westValid){
DFS(i,jWest);
}
if(eastValid){
DFS(i, jEast);
}
if(southValid){
DFS(iSouth,j);
}
if(northValid)
{
DFS(iNorth,j);
}
}
Worked well, thanks for the answers.
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