From 384603dc37bf5148810c89546807f7fb2686d26f Mon Sep 17 00:00:00 2001
From: Diptanshu bhawsar <Diptanshubhawsar50@gmail.com>
Date: Mon, 23 Oct 2023 17:31:15 +0530
Subject: [PATCH] feat: Implement N-Queens problem solution using backtracking

---
 n_queens.py | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 n_queens.py

diff --git a/n_queens.py b/n_queens.py
new file mode 100644
index 0000000..f4218e0
--- /dev/null
+++ b/n_queens.py
@@ -0,0 +1,46 @@
+def is_safe(board, row, col, N):
+    # Check if there's a queen in the same column
+    for i in range(row):
+        if board[i][col] == 1:
+            return False
+
+    # Check upper-left diagonal
+    for i, j in zip(range(row, -1, -1), range(col, -1, -1)):
+        if board[i][j] == 1:
+            return False
+
+    # Check upper-right diagonal
+    for i, j in zip(range(row, -1, -1), range(col, N)):
+        if board[i][j] == 1:
+            return False
+
+    return True
+
+def solve_n_queens(N):
+    board = [[0 for _ in range(N)] for _ in range(N)]
+    if solve_util(board, 0, N) is False:
+        print("No solution exists")
+    else:
+        print_solution(board)
+
+def solve_util(board, row, N):
+    if row == N:
+        return True
+
+    for col in range(N):
+        if is_safe(board, row, col, N):
+            board[row][col] = 1
+
+            if solve_util(board, row + 1, N):
+                return True
+
+            board[row][col] = 0  # Backtrack
+
+    return False
+
+def print_solution(board):
+    for row in board:
+        print(" ".join(["Q" if cell == 1 else "." for cell in row]))
+
+N = 8  # Change N to solve for different board sizes
+solve_n_queens(N)