Problem
Encapsulation keeps an object's data private and only changes it through methods that enforce the rules. A bank account's balance can only change through deposit and withdraw.
Start with a balance of 0 and process the operations, each deposit <amount> or withdraw <amount>:
- An amount that is 0 or negative is rejected.
- A withdrawal larger than the current balance is rejected.
- Otherwise the balance changes.
Implement bank_account_rules(operations).
Input
operations: The operations, in order.
Output
Return [final_balance, rejected_count].
Constraints
0 ≤ number of operations ≤ 100,000
−10^9 ≤ amount ≤ 10^9
Examples
Input:
operations = ["deposit 100", "withdraw 30", "withdraw 200"]
Expected output:
expected = [70, 1]Input:
std::vector<std::string> operations = {"deposit 100", "withdraw 30", "withdraw 200"};
Expected output:
std::vector<long long> expected = {70, 1};Input:
string[] operations = new string[] {"deposit 100", "withdraw 30", "withdraw 200"};
Expected output:
long[] expected = new long[] {70, 1};Explanation
100 − 30 leaves 70; withdrawing 200 would overdraw the account, so it is rejected: [70, 1].
Input:
operations = ["deposit -5", "withdraw 0", "deposit 10"]
Expected output:
expected = [10, 2]Input:
std::vector<std::string> operations = {"deposit -5", "withdraw 0", "deposit 10"};
Expected output:
std::vector<long long> expected = {10, 2};Input:
string[] operations = new string[] {"deposit -5", "withdraw 0", "deposit 10"};
Expected output:
long[] expected = new long[] {10, 2};Explanation
The negative deposit and the zero withdrawal are both rejected; the last deposit succeeds: [10, 2].
How to approach it
Try on your own first, then open one hint at a time.
Hint 1
Keep the balance private and change it only in deposit and withdraw.
Hint 2
Reject amounts of 0 or less before anything else.
Hint 3
A withdrawal may not take the balance below zero.
Expected complexity
O(number of operations) time, O(1) extra space
References
This challenge is adapted for CodeUtility. Follow the statement and constraints above.