r"""
Nearest Neighbor Heuristic Solver
"""
# Copyright (c) 2024 Thinklab@SJTU
# ML4CO-Kit is licensed under Mulan PSL v2.
# You can use this software according to the terms and conditions of the Mulan PSL v2.
# You may obtain a copy of Mulan PSL v2 at:
# http://license.coscl.org.cn/MulanPSL2
# THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
# EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
# MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
# See the Mulan PSL v2 for more details.
from ml4co_kit.optimizer.base import OptimizerBase
from ml4co_kit.task.base import TaskBase, TASK_TYPE
from ml4co_kit.solver.base import SolverBase, SOLVER_TYPE
from .lib.nearest.tsp_nearest import tsp_nearest
from .lib.nearest.cvrp_nearest import cvrp_nearest
[docs]class NearestSolver(SolverBase):
"""
Nearest Neighbor Heuristic Solver
Last Update: 2026-05-26
"""
def __init__(self, optimizer: OptimizerBase = None):
super(NearestSolver, self).__init__(
solver_type=SOLVER_TYPE.NEAREST, optimizer=optimizer
)
def _solve(self, task_data: TaskBase):
"""Solve the task data using nearest-neighbor heuristic."""
if task_data.task_type == TASK_TYPE.TSP:
return tsp_nearest(task_data=task_data)
elif task_data.task_type == TASK_TYPE.CVRP:
return cvrp_nearest(task_data=task_data)
else:
raise ValueError(
f"Solver {self.solver_type} is not supported for {task_data.task_type}."
)