Jenna Williams

Greenhorn

Posts: 1

posted 14 years ago

Hi everyone. I have a problem and would like some help. I would ask that rather than post the whole solution, you gently nudge me in the right direction as I am trying very hard to learn java

Ok, here is the problem. I am working on an assignment for school which involves testing all possible positions on a board of a determined size that a chess queen can occupy without being able to take the other queens.

I have the array all set up and can print the board out. The first Queen always starts at [0][0] of the board array. Now, I need to place a queen in the next position and then test to see whether any other queens can take it. My original thoughts were to create 2 arrays that contain the x/y directions of the moves a queen can make

ie. xPos = {-1,-1,0,1,1,1,0,-1};

yPos = {0,-1,-1,-1,0,1,1,1};

then use these to step back through the array and test for a 'Q'.

This is where I get stuck, how can I utilize this or another solution in a recursive method. That is a condition of the assignment, I must use a recursive method to place and test the queens.

If anyone needs any more information from me please ask and thankyou for taking the time to read/reply.

Ok, here is the problem. I am working on an assignment for school which involves testing all possible positions on a board of a determined size that a chess queen can occupy without being able to take the other queens.

I have the array all set up and can print the board out. The first Queen always starts at [0][0] of the board array. Now, I need to place a queen in the next position and then test to see whether any other queens can take it. My original thoughts were to create 2 arrays that contain the x/y directions of the moves a queen can make

ie. xPos = {-1,-1,0,1,1,1,0,-1};

yPos = {0,-1,-1,-1,0,1,1,1};

then use these to step back through the array and test for a 'Q'.

This is where I get stuck, how can I utilize this or another solution in a recursive method. That is a condition of the assignment, I must use a recursive method to place and test the queens.

If anyone needs any more information from me please ask and thankyou for taking the time to read/reply.

posted 14 years ago

The problem you're working on is a well-known problem called the "N Queens Problem." The best hint I can give you is to go to Google and type in "N Queens". There are a dozen excellent links on the first page.

Another hint: try to solve the problem conceptually, before trying to solve it in Java. I.e., don't think in terms of "2-d arrays" first. Think in terms of a real chessboard, and looking and searching.

Final hint: many simple solutions to this problem are recursive -- i.e., they will use functions that call themselves.

Another hint: try to solve the problem conceptually, before trying to solve it in Java. I.e., don't think in terms of "2-d arrays" first. Think in terms of a real chessboard, and looking and searching.

Final hint: many simple solutions to this problem are recursive -- i.e., they will use functions that call themselves.

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