50!

JYPARK/41to50/50.py

@@ -0,0 +1,19 @@
+def solution(n):
+    def check(ls, new):
+        for i in range(len(ls)):
+            if new == ls[i] or (len(ls)-i) == abs(ls[i]-new):
+                return False
+        return True
+    def dfs(n, ls):
+        if len(ls) == n:
+            return 1
+        cnt = 0
+        for i in range(n):
+            if check(ls, i):
+                cnt += dfs(n, ls+[i])
+        return cnt
+
+    return dfs(n, [])
+
+n = 4
+print(solution(n))