Given a 5x5 chess board, place the fewest number of queens possible on the board such that no queens are under attack but every other space is under attack.
The fewest number of queens is 3.
One of the valid solutions is as follows:
a b c d e
+------------------------+
5 | Q . . . .| 5
+-------------------------+
4 | . . . . . | 4
+--------------------------+
3 | , . . Q . | 3
+---------------------------+
2 | . . . . . | 2
+---------------------------+
1 | . . Q . . | 1
+----------------------------+
a b c d e
Edited on June 30, 2022, 11:00 pm