Added python version of n-queen problem, from git repo provided by Prathamesh Patil.

Codes/Python/Code-A5 (N-Queen).py

@@ -0,0 +1,74 @@
+# Code-A5 (N-Queen)
+
+def print_board(board, n):
+    for i in range(n):
+        for j in range(n):
+            print(board[i][j], end=" ")
+        print()
+    print()  # blank line between solutions
+
+
+def is_safe(board, row, col, n):
+    # Check column
+    for i in range(row):
+        if board[i][col] == 1:
+            return False
+
+    # Check upper-left diagonal
+    i, j = row, col
+    while i >= 0 and j >= 0:
+        if board[i][j] == 1:
+            return False
+        i -= 1
+        j -= 1
+
+    # Check upper-right diagonal
+    i, j = row, col
+    while i >= 0 and j < n:
+        if board[i][j] == 1:
+            return False
+        i -= 1
+        j += 1
+
+    return True
+
+
+def solve_n_queens(board, row, n):
+    if row == n:
+        print_board(board, n)
+        return True
+
+    res = False
+    for col in range(n):
+        if is_safe(board, row, col, n):
+            board[row][col] = 1
+            res = solve_n_queens(board, row + 1, n) or res
+            board[row][col] = 0  # backtrack
+
+    return res
+
+
+# Main program
+n = int(input("Enter number of queens: "))
+board = [[0 for _ in range(n)] for _ in range(n)]
+
+print(f"\nSolutions for {n}-Queens Problem:\n")
+if not solve_n_queens(board, 0, n):
+    print("No solution exists!")
+
+# SAMPLE OUTPUT
+"""
+Enter number of queens: 4
+
+Solutions for 4-Queens Problem:
+
+0 1 0 0 
+0 0 0 1 
+1 0 0 0 
+0 0 1 0 
+
+0 0 1 0 
+1 0 0 0 
+0 0 0 1 
+0 1 0 0 
+"""