Puzzle 6: A Profusion of Queens

Can you place N queens on a board with N columns and N rows so no two queens threaten each other? The 8 queens problem on a chessboard is a special case. Prof. Devadas describes a general solution to the N queens problem that uses recursive backtracking search.

Puzzle Description

• A Profusion of Queens (PDF)

Python Code

• gcd.py (PY)
• nqueens.py (PY)

Assignment

• Do one or more of the exercises in A Profusion of Queens puzzle.

Solution

• nqueens-exercise1.py (PY)

Programming Constructs and Algorithmic Paradigms Covered in this Puzzle

• Recursive procedures
• Exhaustive search through recursion