#73
Analyze a Tic-Tac-Toe Board
| Difficulty: | Hard |
| Topics: | game |
A tic-tac-toe board is represented by
a two dimensional vector.
X is represented by :x, O is represented by :o,
and empty is represented by :e.
A player wins by placing three Xs or three Os
in a horizontal, vertical, or diagonal row.
Write a function which analyzes a tic-tac-toe board
and returns :x if X has won, :o if O has won,
and nil if neither player has won.
 | (= nil (__ [[:e :e :e]
[:e :e :e]
[:e :e :e]])) |
| (= :x (__ [[:x :e :o]
[:x :e :e]
[:x :e :o]])) |
| (= :o (__ [[:e :x :e]
[:o :o :o]
[:x :e :x]])) |
| (= nil (__ [[:x :e :o]
[:x :x :e]
[:o :x :o]])) |
| (= :x (__ [[:x :e :e]
[:o :x :e]
[:o :e :x]])) |
| (= :o (__ [[:x :e :o]
[:x :o :e]
[:o :e :x]])) |
| (= nil (__ [[:x :o :x]
[:x :o :x]
[:o :x :o]])) |