Merge pull request #382 from Vidhi-bhutia/patch-2

Create N-Queens.py

Artificial Intelligence/N-Queens.py

@@ -0,0 +1,56 @@
+def print_board(board):
+    for row in board:
+        print(" ".join("Q" if cell else "." for cell in row))
+    print()
+
+def is_safe(board, row, col):
+    for i in range(row):
+        if board[i][col]:
+            return False
+
+    i, j = row, col
+    while i >= 0 and j >= 0:
+        if board[i][j]:
+            return False
+        i -= 1
+        j -= 1
+
+    i, j = row, col
+    while i >= 0 and j < len(board):
+        if board[i][j]:
+            return False
+        i -= 1
+        j += 1
+
+    return True
+
+def solve_queens(board, row, solutions):
+    if row >= len(board):
+        solutions.append([row[:] for row in board])  
+        return
+
+    for col in range(len(board)):
+        if is_safe(board, row, col):
+            board[row][col] = True
+            solve_queens(board, row + 1, solutions)
+            board[row][col] = False
+
+def eight_queens():
+    size = int(input("Enter size of the board: "))
+    while (size < 0):
+        print("Please enter a positive number! ")
+        size = int(input("Enter size of the board: "))
+
+    board = [[False for _ in range(size)] for _ in range(size)]
+    solutions = []
+    solve_queens(board, 0, solutions)
+
+    if not solutions:
+        print("No solution exists.")
+    else:
+        print(f"Found {len(solutions)} solutions:")
+        for i, solution in enumerate(solutions):
+            print(f"Solution {i + 1}:")
+            print_board(solution)
+
+eight_queens()