Package g2201_2300.s2241_design_an_atm_machine

Class ATM

java.lang.Object
g2201_2300.s2241_design_an_atm_machine.ATM
public class ATM extends Object
2241 - Design an ATM Machine.<p>Medium</p> <p>There is an ATM machine that stores banknotes of <code>5</code> denominations: <code>20</code>, <code>50</code>, <code>100</code>, <code>200</code>, and <code>500</code> dollars. Initially the ATM is empty. The user can use the machine to deposit or withdraw any amount of money.</p> <p>When withdrawing, the machine prioritizes using banknotes of <strong>larger</strong> values.</p> <ul> <li>For example, if you want to withdraw <code>$300</code> and there are <code>2</code> <code>$50</code> banknotes, <code>1</code> <code>$100</code> banknote, and <code>1</code> <code>$200</code> banknote, then the machine will use the <code>$100</code> and <code>$200</code> banknotes.</li> <li>However, if you try to withdraw <code>$600</code> and there are <code>3</code> <code>$200</code> banknotes and <code>1</code> <code>$500</code> banknote, then the withdraw request will be rejected because the machine will first try to use the <code>$500</code> banknote and then be unable to use banknotes to complete the remaining <code>$100</code>. Note that the machine is <strong>not</strong> allowed to use the <code>$200</code> banknotes instead of the <code>$500</code> banknote.</li> </ul> <p>Implement the ATM class:</p> <ul> <li><code>ATM()</code> Initializes the ATM object.</li> <li><code>void deposit(int[] banknotesCount)</code> Deposits new banknotes in the order <code>$20</code>, <code>$50</code>, <code>$100</code>, <code>$200</code>, and <code>$500</code>.</li> <li><code>int[] withdraw(int amount)</code> Returns an array of length <code>5</code> of the number of banknotes that will be handed to the user in the order <code>$20</code>, <code>$50</code>, <code>$100</code>, <code>$200</code>, and <code>$500</code>, and update the number of banknotes in the ATM after withdrawing. Returns <code>[-1]</code> if it is not possible (do <strong>not</strong> withdraw any banknotes in this case).</li> </ul> <p><strong>Example 1:</strong></p> <p><strong>Input</strong></p> <p>[&ldquo;ATM&rdquo;, &ldquo;deposit&rdquo;, &ldquo;withdraw&rdquo;, &ldquo;deposit&rdquo;, &ldquo;withdraw&rdquo;, &ldquo;withdraw&rdquo;]</p> <p>[ [], <a href="0,0,1,2,1">0,0,1,2,1</a>, [600], <a href="0,1,0,1,1">0,1,0,1,1</a>, [600], [550]]</p> <p><strong>Output:</strong> [null, null, [0,0,1,0,1], null, [-1], [0,1,0,0,1]]</p> <p><strong>Explanation:</strong></p> <pre><code> ATM atm = new ATM(); atm.deposit([0,0,1,2,1]); // Deposits 1 $100 banknote, 2 $200 banknotes, // and 1 $500 banknote. atm.withdraw(600); // Returns [0,0,1,0,1]. The machine uses 1 $100 banknote // and 1 $500 banknote. The banknotes left over in the // machine are [0,0,0,2,0]. atm.deposit([0,1,0,1,1]); // Deposits 1 $50, $200, and $500 banknote. // The banknotes in the machine are now [0,1,0,3,1]. atm.withdraw(600); // Returns [-1]. The machine will try to use a $500 banknote // and then be unable to complete the remaining $100, // so the withdraw request will be rejected. // Since the request is rejected, the number of banknotes // in the machine is not modified. atm.withdraw(550); // Returns [0,1,0,0,1]. The machine uses 1 $50 banknote // and 1 $500 banknote. </code></pre> <p><strong>Constraints:</strong></p> <ul> <li><code>banknotesCount.length == 5</code></li> <li><code>0 <= banknotesCount[i] <= 10<sup>9</sup></code></li> <li><code>1 <= amount <= 10<sup>9</sup></code></li> <li>At most <code>5000</code> calls <strong>in total</strong> will be made to <code>withdraw</code> and <code>deposit</code>.</li> <li>At least <strong>one</strong> call will be made to each function <code>withdraw</code> and <code>deposit</code>.</li> </ul>

  • Constructor Details

    • ATM

      public ATM()

  • Method Details

    • deposit

      public void deposit(int[] banknotesCount)

    • withdraw

      public int[] withdraw(int amount)