init

Tutorium/tut05/src/data_classes_solution.py

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+from dataclasses import dataclass
+
+
+def gcd(a: int, b: int) -> int:
+    x = abs(a)
+    y = abs(b)
+    while (y):
+        x, y = y, x % y
+    return x
+
+
+def shorten_fraction(fraction: 'Fraction') -> 'Fraction':
+    g: int = gcd(fraction.divident, fraction.divisor)
+    return Fraction(fraction.divident // g, fraction.divisor // g)
+
+
+@dataclass
+class Fraction:
+    divident: int
+    divisor: int
+
+    def __neg__(self: 'Fraction') -> 'Fraction':
+        return -1 * self
+
+    def __mul__(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        if isinstance(o, int):
+            o = Fraction(o, 1)
+        return shorten_fraction(Fraction(self.divident * o.divident,
+                                         self.divisor * self.divisor))
+
+    def __rmul__(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        return self * o
+
+    def __truediv__(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        if isinstance(o, int):
+            o = Fraction(o, 1)
+        return shorten_fraction(Fraction(self.divident * o.divisor,
+                                         self.divisor * o.divident))
+
+    def __rtruediv___(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        return self / o
+
+    def __add__(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        if isinstance(o, int):
+            o = Fraction(o, 1)
+        g: int = gcd(self.divisor, o.divisor)
+        l: int = abs(self.divisor * o.divisor) // g
+        return shorten_fraction(Fraction(self.divident
+                                         * (l // self.divisor)
+                                         + o.divident
+                                         * (l // o.divisor), l))
+
+    def __radd__(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        return self + o
+
+    def __sub__(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        if isinstance(o, int):
+            o = Fraction(o, 1)
+        return self + -o
+
+    def __rsub__(self: 'Fraction', o: 'Fraction | int') -> 'Fraction':
+        return self - o
+
+    def __eq__(self: 'Fraction', o: 'Fraction | int') -> bool:
+        if isinstance(o, int):
+            o = Fraction(o, 1)
+        shorten_self: 'Fraction' = shorten_fraction(self)
+        shorten_o: 'Fraction' = shorten_fraction(o)
+        return (shorten_self.divident == shorten_o.divident
+                and shorten_self.divisor == shorten_o.divisor)
+
+    def __neq__(self: 'Fraction', o: 'Fraction | int') -> bool:
+        return not (self == o)
+
+    def __str__(self: 'Fraction'):
+        return f"({self.divident} / {self.divisor})"
+
+
+if __name__ == "__main__":
+    assert Fraction(1, 1) == 1
+    assert Fraction(1, 2) == (out := Fraction(2, 4) /
+                              Fraction(g := gcd(2, 4), g)), f"!= {out}"
+    assert (sol := Fraction(9, 20)) == (
+        res := Fraction(1, 5) + Fraction(1, 4)), f"!= {out}"
+    assert (sol := Fraction(-9, 20)) == (
+        res := Fraction(1, -5) + Fraction(-1, 4)), f"!= {out}"
+    assert (sol := Fraction(-1, 20)) == (
+        res := Fraction(1, 5) + Fraction(-1, 4)), f"!= {out}"