Added Proof of Stake(PoS) algorithm

blockchain/proof_of_stake.py

@@ -0,0 +1,49 @@
+import random
+from typing import List
+
+
+class Validator:
+    """
+    Represents a validator in a Proof of Stake system.
+
+    Attributes:
+        name (str): The name of the validator.
+        stake (int): The amount of stake (coins) the validator holds.
+    """
+
+    def __init__(self, name: str, stake: int):
+        """
+        Initializes a new validator with a given name and stake.
+
+        Args:
+            name (str): The name of the validator.
+            stake (int): The amount of stake the validator has.
+        """
+        self.name = name
+        self.stake = stake
+
+
+def choose_validator(validators: List[Validator]) -> Validator:
+    """
+    Selects a validator to create the next block based on the weight of their stake.
+
+    The higher the stake, the greater the chance to be selected.
+
+    Args:
+        validators (List[Validator]): A list of Validator objects.
+
+    Returns:
+        Validator: The selected validator based on weighted random selection.
+
+    Example:
+        >>> validators = [Validator("Alice", 50), Validator("Bob", 30), Validator("Charlie", 20)]
+        >>> chosen = choose_validator(validators)
+        >>> isinstance(chosen, Validator)
+        True
+    """
+    total_stake = sum(v.stake for v in validators)
+    weighted_validators = [(v, v.stake / total_stake) for v in validators]
+    selected = random.choices(
+        [v[0] for v in weighted_validators], weights=[v[1] for v in weighted_validators]
+    )
+    return selected[0]