Initial commit

sum_strings/solution.py

@@ -0,0 +1,11 @@
+# https://www.codewars.com/kata/5324945e2ece5e1f32000370/
+
+def sum_strings(s1, s2):
+    res = ""
+    carry = 0
+    s1, s2 = s1.zfill(len(s2)), s2.zfill(len(s1))
+    for d1, d2 in zip(s1[::-1], s2[::-1]):
+        carry, total = divmod(int(d1) + int(d2) + carry, 10)
+        res += str(total)
+
+    return (str(carry) + res[::-1]).lstrip('0') or '0'

sum_strings/tests.py

@@ -0,0 +1,93 @@
+import random
+import codewars_test as test
+from string import digits
+from solution import sum_strings
+
+    
+def rand_str_num():
+    return ''.join(
+        random.choice(digits)
+        for _ in range(random.randint(0, 1000))
+    )
+    
+def __this_is_the_sol(x, y):
+    out, ret = '', 0
+    
+    for c_x, c_y in zip(x.zfill(len(y))[::-1], y.zfill(len(x))[::-1]):
+        ret, d = divmod(int(c_x) + int(c_y) + ret, 10)
+        out += str(d)
+    
+    out = f"{out}{'1' * ret}"[::-1] or '0'
+    return out if len(out) < 2 else out.lstrip('0')
+
+
+@test.describe('Basic tests')
+def test_examples():
+
+    @test.it('Example tests')
+    def basic_tests():
+        test.assert_equals(sum_strings("1", "1"), "2")
+        test.assert_equals(sum_strings("123", "456"), "579")
+
+    @test.it('Fixed tests')
+    def basic_test():
+        test.assert_equals(sum_strings("10", "20"), "30")
+        test.assert_equals(sum_strings("200", "100"), "300")
+
+        test.assert_equals(sum_strings("99", "1"), "100")
+        test.assert_equals(sum_strings("42", "69"), "111")
+
+        test.assert_equals(sum_strings("2999", "302"), "3301")
+        test.assert_equals(sum_strings("800", "9567"), "10367")
+        
+        test.assert_equals(sum_strings("00103", "08567"), "8670")
+        test.assert_equals(sum_strings("0", "0"), "0")
+
+        test.assert_equals(sum_strings("0", "5"), "5")
+        test.assert_equals(sum_strings("5", "0"), "5")
+        
+        test.assert_equals(sum_strings("0", ""), "0")
+        test.assert_equals(sum_strings("", ""), "0")
+
+        test.assert_equals(sum_strings("9999", ""), "9999")
+        test.assert_equals(sum_strings("", "9999"), "9999")
+        
+        test.assert_equals(sum_strings("9999999999999999", "1"), "10000000000000000")
+        test.assert_equals(sum_strings("1", "9999999999999999"), "10000000000000000")
+
+        test.assert_equals(
+            sum_strings(
+                "712569312664357328695151392", 
+                "8100824045303269669937"
+            ),
+            "712577413488402631964821329",
+        )
+        
+        test.assert_equals(
+            sum_strings(
+                "50095301248058391139327916261", 
+                "81055900096023504197206408605"
+            ),
+            "131151201344081895336534324866"
+        )
+        
+    @test.it('Random tests')
+    def basic_test():
+        x = rand_str_num()
+        y = rand_str_num()
+        
+        for _ in range(100):
+            test.assert_equals(
+                sum_strings(x, y),
+                __this_is_the_sol(x, y)
+            )
+
+    @test.it('Is it fast enough?')
+    def basic_test():
+        x = str(random.randint(10, 99)) * random.randint(1_000_000, 1_100_000)
+        y = str(random.randint(10, 99)) * random.randint(1_000_000, 1_100_000)
+
+        test.expect(
+            sum_strings(x, y) == __this_is_the_sol(x, y),
+            "big test failed"
+        )