Merge pull request #606 from Priyank-Gaur/main

DP problem: Queens on Chessboard

Author: Pradeepsingh61

Python/dynamic_programming/Queens_on_Chessboard.py

@@ -0,0 +1,55 @@
+def checker(queens,i,j):
+    for k in queens:
+        if k[0] == i:
+            return False
+        if k[1] == j:
+            return False
+        if abs(k[0]-i) == abs(k[1]-j):
+            return False
+        if j-2>=0 and i+1<n:
+            if k[0]==j-2 and k[1]==i+1:
+                return False
+        if j-2>=0 and i-1>=0:
+            if k[0]==j-2 and k[1]==i-1:
+                return False
+        if j-1>=0 and i+1<n:
+            if k[0]==j-2 and k[1]==i+1:
+                return False
+        if j-2>=0 and i+1<n:
+            if k[0]==j-2 and k[1]==i+1:
+                return False
+
+    return True
+
+
+
+board = []
+for _ in range(8):
+    row = list(input())
+    board.append(row)
+# print(board)
+
+queens = []
+n = 8
+count = [0]
+def main(i):
+    if i==n:
+        count[0]+=1
+        return
+    for j in range(8):
+        if queens ==[] and board[i][j]!="*":
+            queens.append([i,j])
+            main(i+1)
+            queens.pop()
+        else:
+            if checker(queens,i,j) and board[i][j]!="*":
+                queens.append([i,j])
+                main(i+1)
+                queens.pop()
+main(0)
+print(count[0])
+
+                
+
+
+