diff --git a/days/day1.py b/days/day1.py
index 8d32ce6..888b265 100644
--- a/days/day1.py
+++ b/days/day1.py
@@ -6,27 +6,22 @@ class Day1(unittest.TestCase):
 
     def calc_fuel(self, mass):
         fuel = mass // 3 - 2
-        if(fuel > 0):
-            return fuel + self.calc_fuel(fuel)
-        else:
-            return 0
+        return fuel + self.calc_fuel(fuel) if fuel > 0 else 0
 
     def test_day1a(self):
         fuel = 0
         with open(self.inputfile) as fp:
-            value = fp.readline()
-            while value:
-                fuel += int(value) // 3 - 2
-                value = fp.readline()
+            for _, line in enumerate(fp):
+                fuel += int(line) // 3 - 2
         self.assertEqual(fuel, 3402609)
 
     def test_day1b(self):
         with open(self.inputfile) as fp:
-            line = fp.readline()
-            sumfuel = 0
-            while line:
-                sumfuel += self.calc_fuel(int(line))
-                line = fp.readline()
+            for _, line in enumerate(fp):
+                sumfuel = 0
+                while line:
+                    sumfuel += self.calc_fuel(int(line))
+                    line = fp.readline()
         self.assertEqual(sumfuel, 5101025)
 
 if __name__ == "__main__":
diff --git a/days/day4.py b/days/day4.py
index 479b435..db947b6 100644
--- a/days/day4.py
+++ b/days/day4.py
@@ -1,50 +1,23 @@
 import unittest
 import os
+from collections import Counter
 
 class Day4(unittest.TestCase):
-    def num_to_array(self, num):
-        arr = []
-        while num != 0:
-            arr.append(num % 10)
-            num = num //10
-        arr.reverse()
-        return arr
-
     def check_num(self, num):
-        numarr = self.num_to_array(num)
-        last = numarr[0]
-        adj = False
+        numarr = [int(d) for d in (str(num))]
         for p in range(1,6):
-            val = numarr[p]
-            if last > val:
+            if numarr[p-1] > numarr[p]:
                 return False
-            if last == val:
-                adj = True
-            last = val
-        return adj
+        c = Counter(str(num))
+        return len({k: v for k, v in c.items() if v >= 2}) > 0
 
     def check_num_grp(self, num):
-        numarr = self.num_to_array(num)
-        last = numarr[0]
-        adj = False
-        candidate = False
-        finished = False
+        numarr = [int(d) for d in (str(num))]
         for p in range(1,6):
-            val = numarr[p]
-            if last > val:
+            if numarr[p-1] > numarr[p]:
                 return False
-            if last == val:
-                if adj:
-                    candidate = False
-                else:
-                    candidate = True
-                adj = True
-            else:
-                adj = False
-                if candidate:
-                    finished = True
-            last = val
-        return finished or candidate
+        c = Counter(str(num))
+        return len({k: v for k, v in c.items() if v == 2}) > 0
 
     def test_day4a(self):
         counter = 0
@@ -54,8 +27,6 @@ class Day4(unittest.TestCase):
         self.assertEqual(counter, 1686)
 
     def test_day4b(self):
-        self.assertTrue(self.check_num_grp(112233))
-        self.assertFalse(self.check_num_grp(123444))
         counter = 0
         for num in range(168630,718099):
             if self.check_num_grp(num) == True: