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The n-queens puzzle is the problem of placing **n** queens on a (**n×n)** chessboard such that no two queens can attack each other.

Given an integer n, find all distinct solutions to the n-queens puzzle. Each solution contains distinct board configurations of the n-queens’ placement, where the solutions are a permutation of [1,2,3..n] in increasing order, here the number in the *ith* place denotes that the *ith*-column queen is placed in the row with that number. For eg below figure represents a chessboard [3 1 4 2].

**Example 1:**

**Input:**
1
**Output:**
[1]
**Explaination:**
Only one queen can be placed
in the single cell available.

**Example 2:**

**Input:**
4
**Output:**
[2 4 1 3 ] [3 1 4 2 ]
**Explaination:**
These are the 2 possible solutions.

**Your Task:**

You do not need to read input or print anything. Your task is to complete the function **nQueen()** which takes n as input parameter and returns a list containing all the possible chessboard configurations in sorted order. Return an empty list if no solution exists.

**Expected Time Complexity:** O(n!)

**Expected Auxiliary Space:** O(n^{2})

**Constraints:**

1 ≤ n ≤ 10

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N-Queen Problem

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