[autoparallel] standardize the code structure (#1469)

colossalai/auto_parallel/solver/sharding_strategy.py

+from dataclasses import dataclass
+from colossalai.tensor.sharding_spec import ShardingSpec
+from typing import Dict, List
+
+
+@dataclass
 class ShardingStrategy:
     '''
     ShardingStrategy is a structure containing sharding strategies of inputs and output of this node
@@ -15,21 +21,13 @@ class ShardingStrategy:
         input_shardings(List(ShardingSpec)): The ShardingSpecs of the input nodes.
     '''
 
-    def __init__(self,
-                 name,
-                 output_sharding_spec,
-                 compute_cost=0,
-                 communication_cost=0,
-                 memory_cost=0,
-                 resharding_costs=None,
-                 input_shardings=None):
-        self.name = name
-        self.output_sharding_spec = output_sharding_spec
-        self.compute_cost = compute_cost
-        self.communication_cost = communication_cost
-        self.memory_cost = memory_cost
-        self.resharding_costs = resharding_costs
-        self.input_shardings = input_shardings
+    name: str
+    output_sharding_spec: ShardingSpec
+    compute_cost: float = 0.
+    communication_cost: float = 0.
+    memory_cost: float = 0.
+    resharding_costs: Dict[int, List[float]] = None
+    input_shardings: ShardingSpec = None
 
 
 class StrategiesVector: