Code in Java Queens problem, where the objective is to place 8 queens on a chess
ID: 3755427 • Letter: C
Question
Code in Java
Queens problem, where the objective is to place 8 queens on a chess board so that no two queens can attack each other. A solution corresponding to a goal state is shown in the picture below.
In this question, your objective is to compare the performance of different crossover operators. The crossover operators you need to program are the following: single point crossover, two point crossover, cut and splice, uniform crossover.
You should use the same representation of a chromosome, fitness function, etc. For example, the chromosome or state for the picture above is 86427531.
Your program should first prompt the user for the following input (just input values on a single line, separated by blank space):
Initial population size
Number of chromosomes to select at each iteration or generation of the GA
Mutation rate
Number of iterations or generations to run the GA for; -1 to run the GA until a goal state isfound.
Other parameters can be hardcoded. Then, it should prompt the user to choose one of the crossover operators from a menu. Add an option to exit the program from this menu. After a crossover operator is selected, the program runs. At the end of the run, your program should print (each output on a separate line):
Values of input and hardcoded parameters used (on a single line, comma-separated, format:- )
Number of iterations or generations of the GA executed
Final state reached
Final state’s fitness function value.
After printing the output, the program should go back to the first menu prompt for another the crossover operator or exit.
Q Q Q Q Q Q Q QExplanation / Answer
/* Java program to solve N Queen Problem using
backtracking */
public class NQueenProblem
{
final int N = 4;
/* A utility function to print solution */
void printSolution(int board[][])
{
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
System.out.print(" " + board[i][j]
+ " ");
System.out.println();
}
}
/* A utility function to check if a queen can
be placed on board[row][col]. Note that this
function is called when "col" queens are already
placeed in columns from 0 to col -1. So we need
to check only left side for attacking queens */
boolean isSafe(int board[][], int row, int col)
{
int i, j;
/* Check this row on left side */
for (i = 0; i < col; i++)
if (board[row][i] == 1)
return false;
/* Check upper diagonal on left side */
for (i=row, j=col; i>=0 && j>=0; i--, j--)
if (board[i][j] == 1)
return false;
/* Check lower diagonal on left side */
for (i=row, j=col; j>=0 && i<N; i++, j--)
if (board[i][j] == 1)
return false;
return true;
}
/* A recursive utility function to solve N
Queen problem */
boolean solveNQUtil(int board[][], int col)
{
/* base case: If all queens are placed
then return true */
if (col >= N)
return true;
/* Consider this column and try placing
this queen in all rows one by one */
for (int i = 0; i < N; i++)
{
/* Check if the queen can be placed on
board[i][col] */
if (isSafe(board, i, col))
{
/* Place this queen in board[i][col] */
board[i][col] = 1;
/* recur to place rest of the queens */
if (solveNQUtil(board, col + 1) == true)
return true;
/* If placing queen in board[i][col]
doesn't lead to a solution then
remove queen from board[i][col] */
board[i][col] = 0; // BACKTRACK
}
}
/* If the queen can not be placed in any row in
this colum col, then return false */
return false;
}
/* This function solves the N Queen problem using
Backtracking. It mainly uses solveNQUtil () to
solve the problem. It returns false if queens
cannot be placed, otherwise, return true and
prints placement of queens in the form of 1s.
Please note that there may be more than one
solutions, this function prints one of the
feasible solutions.*/
boolean solveNQ()
{
int board[][] = {{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 0, 0, 0}
};
if (solveNQUtil(board, 0) == false)
{
System.out.print("Solution does not exist");
return false;
}
printSolution(board);
return true;
}
// driver program to test above function
public static void main(String args[])
{
NQueenProblem Queen = new NQueenProblem();
Queen.solveNQ();
}
}