Moved more problems to Python.

python/e019.py

@@ -0,0 +1,55 @@
+def weekday_generator_function():
+    while True:
+        yield 'Monday'
+        yield 'Tuesday'
+        yield 'Wednesday'
+        yield 'Thursday'
+        yield 'Friday'
+        yield 'Saturday'
+        yield 'Sunday'
+
+
+def day_of_month_generator_function():
+    day, month, year = 1, 1, 1901
+    while year < 2001:
+        yield day
+        day += 1
+        if month == 2:
+            if year % 4 == 0 and (not year % 100 == 0 or year % 400 == 0):
+                if day == 30:
+                    month += 1
+                    day = 1
+            elif day == 29:
+                month += 1
+                day = 1
+        elif month in [9, 4, 6, 11] and day == 31:
+            day = 1
+            month += 1
+        elif month in [1, 3, 5, 7, 8, 10] and day == 32:
+            day = 1
+            month += 1
+        elif month == 12 and day == 32:
+            day = 1
+            month = 1
+            year += 1
+
+
+def euler_019():
+    wds = weekday_generator_function()
+    next(wds)  # get rid of first Monday
+    ds = zip(wds, day_of_month_generator_function())
+    s = len([1 for weekday, date in ds if weekday == "Sunday" and date == 1])
+    return s
+
+
+def euler_019_brain():
+    """ We have 100 years which means
+    1200 months. Every months starts with a day
+    and 1/7 of all days are Sundays. """
+    return 1200 // 7
+
+
+if __name__ == "__main__":
+    assert(euler_019() == 171)
+    assert(euler_019() == euler_019_brain())
+    print("e019.py: {}".format(euler_019()))