weighted_edge.py

# weighted_edge.py
# From Classic Computer Science Problems in Python Chapter 4
# Copyright 2018 David Kopec
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from dataclasses import dataclass
from edge import Edge


@dataclass
class WeightedEdge(Edge):
    weight: float

    def reversed(self) -> WeightedEdge:
        return WeightedEdge(self.v, self.u, self.weight)

    # so that we can order edges by weight to find the minimum weight edge
    def __lt__(self, other: WeightedEdge) -> bool:
        return self.weight < other.weight

    def __str__(self) -> str:
        return f"{self.u} {self.weight}> {self.v}"