fixed empty array case, added test

Author: koss-null

py3/median/link py3/hard/median/linkpy3/median/link renamed to py3/hard/median/link

@@ -12,7 +12,7 @@ def bin_search(self, arr, num, fits=lambda a, b: a == b, le=lambda a, b: a <= b)
                 rg = md - 1
             md = (lf + rg) // 2
 
-        if fits(arr[md], num):
+        if arr and fits(arr[md], num):
             # searching the biggest possible step to each side and do it as many times as possible
             left_step, right_step = 1 << 20, 1 << 20
             lf_offset, rg_offset = 0, 0

py3/median/median.py py3/hard/median/median.pypy3/median/median.py renamed to py3/hard/median/median.py

@@ -0,0 +1,4 @@
+{
+"input": "\n1",
+"output": "1.0"
+}