Multiplication doddling.

doddling/multiplication.py

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+from hypothesis import given
+from hypothesis.strategies import integers
+
+
+def russian_multiplication(x, y):
+    columns = [(x, y)]
+    while x >= 1:
+        columns.append((x := x // 2, y := y * 2))
+    return sum(y for x, y in columns if x % 2)
+
+
+def egyptian_multiplication(x, y):
+    i = 1
+    values = [y]
+    while i < x:
+        i *= 2
+        values.append((y := y * 2))
+    return sum(x for b, x in zip(reversed(f"{x:b}"), values) if b == '1')
+
+
+@given(integers(min_value=0), integers(min_value=0))
+def test_russian_multiplication(x, y):
+    assert russian_multiplication(x, y) == x * y
+
+
+@given(integers(min_value=0), integers(min_value=0))
+def test_egyptian_multiplication(x, y):
+    assert egyptian_multiplication(x, y) == x * y