Greedy-Algorithms: Knapsack first working version

Greedy-Algorithms/cs412_knapsack_fractional.py

@@ -8,12 +8,70 @@ Honor Code and Acknowledgments:
        Comments here on your code and submission.
 """
 
+from dataclasses import dataclass
+from typing import override
+
+
+# I don't like tuples
+@dataclass(frozen=True)
+class KnapsackItem:
+    name: str
+    value: float
+    weight: float
+
+    @property
+    def value_per(self) -> float:
+        return self.value / self.weight
+
+    @override
+    def __str__(self) -> str:
+        return f"{self.name}({self.value:.2f}, {self.weight:.2f})"
+
+    @staticmethod
+    def from_str(string: str) -> "KnapsackItem":
+        values: list[str] = string.split()
+        name, value, weight = values[0], float(values[1]), float(values[2])
+        return KnapsackItem(name, value, weight)
+
+
+def knapsack(
+    capacity: int, items: list[KnapsackItem]
+) -> tuple[list[KnapsackItem], float]:
+    cur_capacity: float = capacity
+    sorted_items: list[KnapsackItem] = sorted(items, key=lambda i: -i.value_per)
+
+    total_value: float = 0.0
+    fractional_items: list[KnapsackItem] = []
+
+    for item in sorted_items:
+        if abs(cur_capacity) < 1e-8:
+            break
+
+        if cur_capacity < item.weight:
+            value: float = item.value_per * cur_capacity
+            total_value += value
+            fractional_items.append(KnapsackItem(item.name, value, cur_capacity))
+            cur_capacity = 0
+        else:
+            total_value += item.value
+            fractional_items.append(KnapsackItem(item.name, item.value, item.weight))
+            cur_capacity -= item.weight
+
+    return fractional_items, total_value
+
 
 # All modules for CS 412 must include a main method that allows it
 # to imported and invoked from other python scripts
 def main():
-    # your code here
+    capacity: int = int(input())
-    pass
+    n: int = int(input())
+
+    items: list[KnapsackItem] = [KnapsackItem.from_str(input()) for _ in range(0, n)]
+
+    fractional_items, total_value = knapsack(capacity, items)
+
+    print(" ".join(map(str, fractional_items)))
+    print(total_value)
 
 
 if __name__ == "__main__":