prod-tech
78 lines
2.0 KiB
Python
78 lines
2.0 KiB
Python
from fastapi import FastAPI
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from pydantic import BaseModel
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from typing import List
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from collections import defaultdict
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app = FastAPI(openapi_url="/optimizetka/openapi.json", docs_url="/optimizetka/docs")
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class Participant(BaseModel):
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id: int
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class Position(BaseModel):
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price: float
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assigned_to_ids: List[int]
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class Transaction(BaseModel):
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owner_id: int
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positions: List[Position]
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class InputData(BaseModel):
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participants: List[Participant]
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transactions: List[Transaction]
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class Debt(BaseModel):
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from_user_id: int
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to_user_id: int
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amount: float
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@app.post("/optimizetka/api/calculate-debts", response_model=List[Debt])
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def calculate_debts(data: InputData) -> List[Debt]:
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balances = defaultdict(float)
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for transaction in data.transactions:
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owner_id = transaction.owner_id
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for position in transaction.positions:
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price = position.price
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assigned_to_ids = position.assigned_to_ids
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share = price / len(assigned_to_ids)
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for participant_id in assigned_to_ids:
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if participant_id != owner_id:
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balances[participant_id] -= share
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balances[owner_id] += share
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debts = []
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creditors = [(p, amount) for p, amount in balances.items() if amount > 0]
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debtors = [(p, -amount) for p, amount in balances.items() if amount < 0]
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i, j = 0, 0
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while i < len(creditors) and j < len(debtors):
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creditor_id, credit_amount = creditors[i]
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debtor_id, debt_amount = debtors[j]
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payment = min(credit_amount, debt_amount)
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debts.append(
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{
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"from_user_id": debtor_id,
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"to_user_id": creditor_id,
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"amount": round(payment, 2),
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}
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)
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creditors[i] = (creditor_id, credit_amount - payment)
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debtors[j] = (debtor_id, debt_amount - payment)
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if creditors[i][1] == 0:
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i += 1
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if debtors[j][1] == 0:
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j += 1
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return debts
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