import torch
import torch.nn as nn

class Actor(nn.Module):
    def __init__(self, state_dim, action_dim, max_action):
        super().__init__()
        self.max_action = max_action
        self.net = nn.Sequential(
            nn.Linear(state_dim, 128), nn.ReLU(),
            nn.Linear(128, 128), nn.ReLU(),
            nn.Linear(128, action_dim)
        )
    def forward(self, state):
        return self.max_action * torch.tanh(self.net(state))

class Critic(nn.Module):
    def __init__(self, state_dim, action_dim):
        super().__init__()
        self.net = nn.Sequential(
            nn.Linear(state_dim + action_dim, 128), nn.ReLU(),
            nn.Linear(128, 128), nn.ReLU(),
            nn.Linear(128, 1)
        )
    def forward(self, state, action):
        return self.net(torch.cat([state, action], dim=1))