Untitled

from typing import List, Dict

def solution(queries: List[List[str]]) -> List[str]:
    balances: Dict[str, int] = {}
    ans = []

    for query in queries:
        op = query[0]

        if op == "CREATE_ACCOUNT":
            _, timestamp, account_id = query

            if account_id in balances:
                ans.append("false")
            else:
                balances[account_id] = 0
                ans.append("true")

        elif op == "DEPOSIT":
            _, timestamp, account_id, amount_str = query
            amount = int(amount_str)

            if account_id not in balances:
                ans.append("")
            else:
                balances[account_id] += amount
                ans.append(str(balances[account_id]))

        elif op == "TRANSFER":
            _, timestamp, source, target, amount_str = query
            amount = int(amount_str)

            if source not in balances:
                ans.append("")
            elif target not in balances:
                ans.append("")
            elif source == target:
                ans.append("")
            elif balances[source] < amount:
                ans.append("")
            else:
                balances[source] -= amount
                balances[target] += amount
                ans.append(str(balances[source]))

    return ans