32. Backtracking, N queens - Part B - Data Structures and Algorithms in Python
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32. Backtracking, N queens - Part B

32. Backtracking, N queens - Part B

The chapter explores the N-Queens problem, detailing how to effectively represent and solve this problem using a backtracking algorithm. It highlights the need for efficient use of space in tracking attacked squares and demonstrates strategies for determining safe positions for queens on a chessboard. The implementation in Python showcases the use of dictionaries for a more compact and efficient representation of board states and queen placements.

15 sections

Sections

Navigate through the learning materials and practice exercises.

  1. 32.1
    Representation Of Attacks In N-Queens Problem

    This section discusses how to efficiently represent attacks in the N-Queens...

  2. 32.1.1
    Attack Representation Strategy

    This section discusses the representation of attacks on a chessboard by...

  3. 32.1.2
    Diagonal Representation

    This section explains how to represent the attack zones of queens in the...

  4. 32.1.3
    Confirming Squares Under Attack

    This section discusses how to manage a queen's attack in chess using an...

  5. 32.2
    Space Optimization Techniques

    This section discusses the strategies for optimizing space in the context of...

  6. 32.2.1
    Using Arrays For Rows, Columns, And Diagonals

    This section discusses how to efficiently use arrays to track attack...

  7. 32.2.2
    Implementation Details

    The section covers how to efficiently implement the attack representation...

  8. 32.3
    Python Implementation And Functions

    This section discusses a Python implementation of the N-Queens problem,...

  9. 32.3.1
    Place Queen Function

    This section discusses the implementation of the Queen placement function...

  10. 32.3.2
    Board Initialization

    This section discusses the initialization of the board for the N-Queens...

  11. 32.3.3
    Checking Free Square

    This section discusses an efficient approach to check if a square in a board...

  12. 32.3.4
    Adding And Undoing Queens

    This section discusses how to efficiently manage the placement and removal...

  13. 32.4
    Finding All Solutions

    This section discusses an optimized data structure approach to track the...

  14. 32.4.1
    Simplified Search Process

    This section discusses the optimization of the search process in a queen...

  15. 32.4.2
    Code Adjustments For Printing All Solutions

    This section discusses adjustments in coding techniques needed to properly...

What we have learnt

  • The N-Queens problem involves placing N queens on an N x N chessboard such that no two queens threaten each other.
  • Efficient representation of the chessboard and tracking of attacked squares can reduce space complexity from O(N^2) to O(N).
  • Backtracking is a key algorithmic strategy used to systematically search for solutions by exploring all possible configurations.

Key Concepts

-- NQueens Problem
A combinatorial problem that involves placing N queens on an N x N chessboard so that no two queens can attack each other.
-- Backtracking
An algorithmic technique for solving problems incrementally, by trying partial solutions and removing them if they fail to meet the conditions.
-- Space Complexity
A measure of the amount of working storage an algorithm needs.

Additional Learning Materials

Supplementary resources to enhance your learning experience.