## Introduction

The N queens problem is a classic puzzle that involves placing N queens on an NxN chessboard in such a way that no two queens threaten each other. This problem can be solved using various programming languages, including Swift and C#. In this article, we will compare the performance of solving the N queens problem using Swift playground and C#.

## Solving the N Queens Problem in Swift Playground

In Swift, we can solve the N queens problem using a backtracking algorithm. The algorithm recursively tries to place a queen in each row of the chessboard, ensuring that no two queens threaten each other. Here is an example implementation in Swift:

```
func solveNQueens(_ n: Int) -> [[String]] {
var board = Array(repeating: Array(repeating: ".", count: n), count: n)
var solutions = [[String]]()
func backtrack(_ row: Int) {
if row == n {
let solution = board.map { String($0) }
solutions.append(solution)
return
}
for col in 0..
``` Bool {
for i in 0..= 0 && j >= 0 {
if board[i][j] == "Q" {
return false
}
i -= 1
j -= 1
}
i = row - 1
j = col + 1
while i >= 0 && j < n {
if board[i][j] == "Q" {
return false
}
i -= 1
j += 1
}
return true
}
backtrack(0)
return solutions
}
let solutions = solveNQueens(8)
for solution in solutions {
print(solution.joined(separator: "n"))
print()
}

## Solving the N Queens Problem in C#

Similarly, we can solve the N queens problem in C# using a backtracking algorithm. The algorithm follows the same logic as the Swift implementation. Here is an example implementation in C#:

```
using System;
using System.Collections.Generic;
public class NQueensProblem
{
public static List
```> SolveNQueens(int n)
{
var board = new string[n, n];
var solutions = new List>();
Backtrack(0);
void Backtrack(int row)
{
if (row == n)
{
var solution = new List();
for (int i = 0; i < n; i++)
{
var rowString = "";
for (int j = 0; j < n; j++)
{
rowString += board[i, j];
}
solution.Add(rowString);
}
solutions.Add(solution);
return;
}
for (int col = 0; col < n; col++)
{
if (IsSafe(row, col))
{
board[row, col] = "Q";
Backtrack(row + 1);
board[row, col] = ".";
}
}
}
bool IsSafe(int row, int col)
{
for (int i = 0; i < row; i++)
{
if (board[i, col] == "Q")
{
return false;
}
}
int x = row - 1;
int y = col - 1;
while (x >= 0 && y >= 0)
{
if (board[x, y] == "Q")
{
return false;
}
x--;
y--;
}
x = row - 1;
y = col + 1;
while (x >= 0 && y < n)
{
if (board[x, y] == "Q")
{
return false;
}
x--;
y++;
}
return true;
}
return solutions;
}
public static void Main(string[] args)
{
var solutions = SolveNQueens(8);
foreach (var solution in solutions)
{
foreach (var row in solution)
{
Console.WriteLine(row);
}
Console.WriteLine();
}
}
}

## Performance Comparison

When comparing the performance of solving the N queens problem using Swift playground and C#, it is important to consider the specific environment and hardware on which the code is executed. However, in general, C# tends to have better performance than Swift due to its optimized runtime and just-in-time (JIT) compilation.

Both implementations use a backtracking algorithm, which has an exponential time complexity of O(N!). This means that the execution time increases rapidly as the size of the chessboard (N) increases. Therefore, for larger values of N, the performance difference between Swift and C# may become more noticeable.

## Conclusion

In conclusion, both Swift and C# can be used to solve the N queens problem efficiently. However, when it comes to performance, C# may have an advantage due to its optimized runtime and JIT compilation. It is important to consider the specific environment and hardware when comparing the performance of different programming languages.