commit d813412bd449c5fe9c3e35a150dd68a1d90c4b2b
Author: Nyeogmi <economicsbat@gmail.com>
Date:   Sun Apr 27 15:28:32 2025 -0700

    RPS: Initial code

diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..8aef7b1
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "python.analysis.typeCheckingMode": "standard"
+}
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diff --git a/main.py b/main.py
new file mode 100644
index 0000000..5b6f11a
--- /dev/null
+++ b/main.py
@@ -0,0 +1,160 @@
+from collections import defaultdict
+import random
+from typing import Callable
+
+
+BAT = "🦇"
+SNAKE = "🐍"
+ROCK = "🗿"
+PAPER = "🗞"
+SCISSORS = "🔪"
+CHOICES = ROCK, PAPER, SCISSORS
+
+VERBS = {
+    ROCK: "THUD!",
+    PAPER: "WHACK!",
+    SCISSORS: "STAB!",
+}
+
+def input_choice[T](prompt: str, options: dict[str, T]) -> T:
+    hint = f"({", ".join(options.keys())})"
+    choice = input(f"{prompt} {hint}: ").upper()
+    while choice not in options:
+        choice = input(f"{hint}): ").upper()
+    return options[choice]
+
+def beats(x: str, y: str):
+    return (x, y) in {(PAPER, ROCK), (SCISSORS, PAPER), (ROCK, SCISSORS)}
+
+
+class Predictor(object):
+    def __init__(self, context_size: int, include_player_moves: bool, include_adversary_moves: bool):
+        self._context_size = context_size
+        self._include_player_moves = include_player_moves
+        self._include_adversary_moves = include_adversary_moves
+
+    def predict(self, history: list[tuple[str, str]]) -> dict[str, float]:
+        context_size = self._context_size
+
+        def _pluck_context(i: int) -> tuple[str, ...]:
+            raw_context = history[i:i + context_size]
+            context_items: list[str] = []
+            for player, adversary in raw_context:
+                if self._include_player_moves:
+                    context_items.append(player)
+                if self._include_player_moves:
+                    context_items.append(adversary)
+                
+            return tuple(context_items)
+
+        observations: dict[str, int] = {c: 1 for c in CHOICES}
+        
+        final_context = _pluck_context(len(history) - context_size)
+        # print(f"final context {self._context_size, self._include_player_moves, self._include_adversary_moves}: {final_context}")
+        # print(f"history: {history} context size: {context_size}")
+
+        for i in range(len(history) - context_size):
+            context = _pluck_context(i)
+            observation, _ = history[i + context_size]
+            # print(f"context: {context} final context: {final_context} observation: {observation}")
+            if context == final_context:
+                observations[observation] += 1
+
+        sum_count = 0
+        for r in CHOICES:
+            sum_count += observations[r]
+
+        return {
+            r: observations[r] / sum_count
+            for r in CHOICES
+        }
+
+class Adversary(object):
+    def __init__(self):
+        self._history: list[tuple[str, str]] = []
+
+    def notify(self, player: str, adversary: str):
+        self._history.append((player, adversary))
+
+    def pick(self):
+        player_probability = self.predict()
+        expected_value = {c: 0.0 for c in CHOICES}
+        for adversary in CHOICES:
+            for player in CHOICES:
+                expected_value[adversary] += (
+                    1.0 if beats(adversary, player) else 
+                    -1.0 if beats(player, adversary) else
+                    0.0
+                ) * player_probability[player]
+        print(f"SNAKE PREDICTIONS: {player_probability}")
+        print(f"SNAKE EV: {expected_value}")
+        max_expected_value = max(expected_value.values())
+        best_choices = [c for c, v in expected_value.items() if v == max_expected_value]
+        return random.choice(best_choices)
+
+    def predict(self) -> dict[str, float]:
+        def _merge(tables: list[dict[str, float]]):
+            out = {}
+            for c in CHOICES:
+                sum_ = 0.0
+                for t in tables:
+                    sum_ += t[c]
+                sum_ /= len(tables)
+                out[c] = sum_
+            return out
+
+
+        tables = []
+        for p in [
+            Predictor(0, include_player_moves=False, include_adversary_moves=False),
+            Predictor(1, include_player_moves=True, include_adversary_moves=False),
+            Predictor(1, include_player_moves=False, include_adversary_moves=True),
+            Predictor(1, include_player_moves=True, include_adversary_moves=True),
+            # Predictor(2, include_player_moves=True, include_adversary_moves=False),
+            # Predictor(2, include_player_moves=False, include_adversary_moves=True),
+            # Predictor(2, include_player_moves=True, include_adversary_moves=True),
+            Predictor(1, include_player_moves=False, include_adversary_moves=True),
+        ]:
+            tables.append(p.predict(self._history))
+        
+        return _merge(tables)
+
+
+def main():
+    counter = 0
+
+    player_score = 0
+    adversary_score = 0
+
+    adversary = Adversary()
+
+    while True:
+        print(f"== Round {counter + 1} ==")
+        print(f"SCORE: {player_score}:{adversary_score}")
+        print()
+        print(f"{SNAKE}: Hsss!")
+        player_choice = input_choice(f"{BAT}", {"R": ROCK, "P": PAPER, "S": SCISSORS})
+        adversary_choice = adversary.pick()
+
+        if beats(player_choice, adversary_choice):
+            player_score += 1
+            msg = "VICTORY!"
+        elif beats(adversary_choice, player_choice):
+            adversary_score += 1
+            msg = "DEFEAT!"
+        else:
+            msg = "DRAW!"
+
+        print()
+        print(f"{BAT}: {player_choice}! {VERBS[player_choice]}")
+        print(f"{SNAKE}: {adversary_choice}! {VERBS[adversary_choice]}")
+        print(msg)
+        print()
+
+        adversary.notify(player_choice, adversary_choice)
+        counter += 1
+
+
+
+if __name__ == "__main__":
+    main()
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