simplify and make %C logic consistent

Lib/_strptime.py

@@ -621,11 +621,6 @@ def parse_int(s):
             # C99 support for century in [0,99] (years 0-9999).
             century = parse_int(found_dict[group_key])
             year = century * 100
-            if century > 0:
-                year = century * 100
-            elif century == 0:
-                # ValueError fix, since MINYEAR = 1 in Lib/_pydatetime.py
-                year = 1
         elif group_key == 'Y':
             year = int(found_dict['Y'])
         elif group_key == 'G':

Lib/test/datetimetester.py

@@ -2226,9 +2226,9 @@ def test_strptime_n_and_t_format(self):
                     )
 
     def test_strptime_C_format(self):
-        # verify cent. 0, zero-padding, modern cent., last supported cent.
-        for c in ('0', '01', '20', '99'):
-            expected_year = int(c) * 100 if int(c) != 0 else 1
+        # verify zero-padding, modern cent., last supported cent.
+        for c in ('01', '20', '99'):
+            expected_year = int(c) * 100
             with self.subTest(format_directive="C", century=c):
                 self.assertEqual(
                     self.theclass.strptime(c, "%C"),

Lib/test/test_strptime.py

@@ -688,9 +688,9 @@ def test_strptime_n_and_t_format(self):
                     )
 
     def test_strptime_C_format(self):
-        # verify cent. 0, zero-padding, modern cent., last supported cent.
-        for c in ('0', '01', '20', '99'):
-            expected_year = int(c) * 100 if int(c) != 0 else 1
+        # verify zero-padding, modern cent., last supported cent.
+        for c in ('01', '20', '99'):
+            expected_year = int(c) * 100
             with self.subTest(format_directive="C", century=c):
                 self.assertEqual(
                     time.strptime(c, "%C"),