Hello GPT-4,

I have a task for you involving code modification. I will provide you with a code snippet that needs some improvement or fixes. Your job is to suggest corrections or enhancements, and then describe these changes in a specific format.

Input:

    Code Snippet: I'll supply a code snippet that might contain issues or could benefit from enhancements.

    Desired Change Format: I need you to provide your suggested changes in this format:

    <line_number>:<new_line_content>
    <line_number>:<new_line_content>

        <line_number>: This refers to the line number in the original code.
        <new_line_content>: This is the revised version of the code line at that line number.

    Additional Instructions:
        Assume the first line of the provided code snippet is line number 1.
        Include comprehensive fixes for syntax errors, logic errors, or performance improvements.
        Preserve the context and functionality of the original code unless stated otherwise.

Example:

Input Code Snippet:

def example_function(x):
return x + 1

exampleFunction(5)

Output Change Format:

2:    return x + 1
4:example_function(5)

That's the format I'd like for your output. Please let me know if you have any questions! Now, let's begin with the code snippet:
 use std::collections::HashMap;
use std::hash::{Hash, Hasher};

#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
enum Suit {
    Clubs,
    Diamonds,
    Hearts,
    Spades,
}

#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
enum Rank {
    Two,
    Three,
    Four,
    Five,
    Six,
    Seven,
    Eight,
    Nine,
    Ten,
    Jack,
    Queen,
    King,
    Ace,
}

#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
struct Card {
    rank: Rank,
    suit: Suit,
}

struct Deck {
    cards: Vec<Card>,
}

impl Deck {
    fn new() -> Self {
        let mut cards = Vec::with_capacity(52);
        for &suit in &[Suit::Clubs, Suit::Diamonds, Suit::Hearts, Suit::Spades] {
            for &rank in &[
                Rank::Two, Rank::Three, Rank::Four, Rank::Five, Rank::Six,
                Rank::Seven, Rank::Eight, Rank::Nine, Rank::Ten, Rank::Jack,
                Rank::Queen, Rank::King, Rank::Ace,
            ] {
                cards.push(Card { rank, suit });
            }
        }
        Self { cards }
    }

    fn shuffle(&mut self) {
        let mut rng = rand::thread_rng();
        self.cards.shuffle(&mut rng);
    }

    fn deal(&mut self) -> Option<Card> {
        self.cards.pop()
    }
}

#[derive(Debug)]
struct GameState {
    player_hands: [Vec<Card>; 2],
    community_cards: Vec<Card>,
    pot: u32,
    current_player: usize,
}

impl GameState {
    fn new(deck: &mut Deck) -> Self {
        let mut player_hands = [Vec::new(), Vec::new()];
        for hand in player_hands.iter_mut() {
            if let Some(card) = deck.deal() {
                hand.push(card);
            }
            if let Some(card) = deck.deal() {
                hand.push(card);
            }
        }

        Self {
            player_hands,
            community_cards: Vec::new(),
            pot: 100, // Starting pot for simulations
            current_player: 0,
        }
    }

    fn is_terminal(&self) -> bool {
        self.community_cards.len() >= 3 // Simplified termination
    }

    fn utility(&self, _player: usize) -> f64 {
        self.pot as f64 / 2.0 // Placeholder utility calculation
    }
}

#[derive(Clone, Debug, PartialEq, Hash)] // Here we add `Hash` to the derive attribute
enum Action {
    Fold,
    Call,
    Bet(f32),
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
enum Position {
    Dealer,
    SmallBlind,
}

#[derive(Debug)]
struct InfoSet {
    private_cards: [Card; 2],
    public_cards: Vec<Card>,
    betting_history: Vec<Action>,
    position: Position,
}

impl Hash for InfoSet {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.private_cards.hash(state);
        self.public_cards.hash(state);
        self.betting_history.hash(state);
        self.position.hash(state);
    }
}

impl PartialEq for InfoSet {
    fn eq(&self, other: &Self) -> bool {
        self.private_cards == other.private_cards
            && self.public_cards == other.public_cards
            && self.betting_history == other.betting_history
            && self.position == other.position
    }
}

impl Eq for InfoSet {}

struct RegretTable {
    table: HashMap<u64, [f64; 3]>,
}

impl RegretTable {
    fn new() -> Self {
        Self {
            table: HashMap::new(),
        }
    }

    fn get_mut(&mut self, key: u64) -> &mut [f64; 3] {
        self.table.entry(key).or_insert([0.0; 3])
    }

    fn get(&self, key: u64) -> &[f64; 3] {
        self.table.get(&key).unwrap_or(&[0.0; 3])
    }
}

struct StrategyTable {
    table: HashMap<u64, [f64; 3]>,
}

impl StrategyTable {
    fn new() -> Self {
        Self {
            table: HashMap::new(),
        }
    }

    fn get_strategy(&mut self, infoset: &InfoSet) -> [f64; 3] {
        let key = compute_infoset_key(infoset);
        let regrets = self.table.entry(key).or_insert([0.0; 3]);
        let sum: f64 = regrets.iter().cloned().filter(|&x| x > 0.0).sum();

        if sum > 0.0 {
            let strategy: Vec<f64> = regrets.iter().map(|&r| if r > 0.0 { r } else { 0.0 }).collect();
            let mut normalized_strategy = [0.0; 3];
            for (i, v) in strategy.iter().enumerate() {
                normalized_strategy[i] = *v / sum;
            }
            normalized_strategy
        } else {
            [1.0 / 3.0; 3]
        }
    }

    fn update_strategy(&mut self, infoset: &InfoSet, strategy: [f64; 3]) {
        self.table.insert(compute_infoset_key(infoset), strategy);
    }
}

fn compute_infoset_key<H: Hash>(t: &H) -> u64 {
    let mut s = std::collections::hash_map::DefaultHasher::new();
    t.hash(&mut s);
    s.finish()
}

fn cfr(
    state: &mut GameState,
    player: usize,
    history: &Vec<Action>,
    probabilities: [f64; 2],
    regrets: &mut RegretTable,
    strategies: &mut StrategyTable,
) -> f64 {
    if state.is_terminal() {
        return state.utility(player);
    }

    let infoset = InfoSet {
        private_cards: [state.player_hands[player][0], state.player_hands[player][1]],
        public_cards: state.community_cards.clone(),
        betting_history: history.clone(),
        position: if player == 0 { Position::Dealer } else { Position::SmallBlind },
    };

    let strategy = strategies.get_strategy(&infoset);
    let mut node_utilities = [0.0; 3];
    let mut node_value = 0.0;

    let pot_size: f32 = state.pot as f32;

    let actions = [
        Action::Fold,
        Action::Call,
        Action::Bet(0.5 * pot_size),
    ];

    for (i, action) in actions.iter().enumerate() {
        let mut next_history = history.clone();
        next_history.push(action.clone());

        let action_probability = strategy[i];
        let new_probabilities = if player == 0 {
            [action_probability * probabilities[0], probabilities[1]]
        } else {
            [probabilities[0], action_probability * probabilities[1]]
        };

        let result_value = cfr(state, player, &next_history, new_probabilities, regrets, strategies);
        node_utilities[i] = result_value;
        node_value += action_probability * result_value;
    }

    let current_regrets = regrets.get_mut(compute_infoset_key(&infoset));
    for (i, action_util) in node_utilities.iter().enumerate() {
        let regret = action_util - node_value;
        current_regrets[i] += probabilities[1 - player] * regret;
    }

    node_value
}

fn train(iterations: u32) {
    let mut regrets = RegretTable::new();
    let mut strategies = StrategyTable::new();

    for _ in 0..iterations {
        let mut deck = Deck::new();
        deck.shuffle();
        let mut game_state = GameState::new(&mut deck);

        for player in 0..2 {
            cfr(
                &mut game_state,
                player,
                &vec![],
                [1.0, 1.0],
                &mut regrets,
                &mut strategies,
            );
        }
    }

    for (key, strategy) in strategies.table.iter() {
        println!("InfoSet: {}, Strategy: {:?}", key, strategy);
    }
}

fn main() {
    train(1000);  // Increase the number of iterations for better learning
}