Day2.py

#Design a Thread-Safe Wallet System with O(1) operations
import threading

class Account:
    def __init__(self,balance=0):
        self.balance=balance
        self.lock=threading.Lock()
    
class WalletSystem:
    def __init__(self):
        self.users={}
        self.lock=threading.Lock()

    def createUser(self,username,balance):
        with self.lock:
            if username in self.users:
                return "User already exists"
            self.users[username]=Account(balance)
            return "User created successfully"
    
    def getBalance(self,username):
        account=self.getAccount(username)
        return account.balance

    def credit(self,username,amount):
        with self.lock:
            if username not in self.users:
                return "User not found"
            self.users[username].balance+=amount
            return "Amount credited successfully"
    
    def debit(self,username,amount):
        with self.lock:
            if username not in self.users:
                return "User not found"
            if self.users[username].balance<amount:
                return "Insufficient balance"
            self.users[username].balance-=amount
            return "Amount debited successfully"
    
    def transfer(self,from_user,to_user,amount):
        account1=self.getAccount(from_user)
        account2=self.getAccount(to_user)
        if account1.balance<amount:
            return "Insufficient balance"
        account1.balance-=amount
        account2.balance+=amount
        return "Amount transferred successfully"

    def getAccount(self,username):
        with self.lock:
            if username not in self.users:
                return "User not found"
            return self.users[username]

def test1():
    wallet=WalletSystem()
    wallet.createUser("Krishna",100)
    def debit50():
        print("Debit:",wallet.debit("Krishna",50))
    def debit70():
        print("Debit:",wallet.debit("Krishna",70))
    t1=threading.Thread(target=debit50)
    t2=threading.Thread(target=debit70)
    t1.start()
    t2.start()
    t1.join()
    t2.join()
    print("Final balance:",wallet.getBalance("Krishna"))

def test2():
    wallet=WalletSystem()
    wallet.createUser("Krishna",100)
    wallet.createUser("Divanshu",50)
    def transfer():
        print("Transfer from Krishna to Divanshu:",wallet.transfer("Krishna","Divanshu",50))
    
    threads=[]
    for i in range(5):
        threads.append(threading.Thread(target=transfer))
    
    for thread in threads:
        thread.start()
    
    for thread in threads:
        thread.join()
    
    print("Final balance of Krishna:",wallet.getBalance("Krishna"))
    print("Final balance of Divanshu:",wallet.getBalance("Divanshu"))
    
if __name__ == "__main__":
    test1()
    test2()