algorithm - Generating all possible combinations with given constraint for Nonogram puzzle (Java) -

my problem have generate possible combinations rows/columns when have constraint. lets have nonogram puzzle , row has size of 40. , have constraints

b,11,g,5,b,9 

i have follow constraints:

• there @ least 1 empty box between 2 blocks of boxes filled same color
• there not have empty box between boxes filled different color
• the order of numbers in legend corresponds order of blocks of boxes (from left right, top bottom)

where letters stands color (i.e. b = blue) , following length of block. have class rules. , rules store in arraylist rules.

public class rule {  public int size; public char color;  public rule(int length, char color){     this.size = length;     this.color= color; } 

now want generate valid combinations rows/cols can add them arraylist rowcombinations

for (int =0 ; < rowsize ; i++){                  rowcombinations.add(makecombinations(some_input)); } 

and makecombinations function return mine custom variable class cspvariable

public class cspvariable {  public arraylist<char[]> storage; public int position; public boolean row;  public cspvariable(int index, boolean row) {     this.position = index;     this.row = row;     this.storage = new arraylist<>(); } 

so recap... given rules want generate possible combinations of letters , store char array storage int cspvariable class.