Problem Description
Initially, you have a bank account balance of 100 dollars. You are given an integer purchaseAmount representing the amount you will spend on a purchase in dollars. When making the purchase, first the purchaseAmount is rounded to the nearest multiple of 10. Then, this rounded amount is removed from your bank account. Return an integer denoting your final bank account balance after this purchase.
Key Insights
- The rounding rule states that amounts ending in 5 or greater are rounded up to the next multiple of 10.
- The account balance starts at 100 dollars, and the final balance is calculated by subtracting the rounded purchase amount.
- The potential purchase amounts range from 0 to 100, making the problem straightforward in terms of calculations.
Space and Time Complexity
Time Complexity: O(1) - The solution involves a constant-time arithmetic operation. Space Complexity: O(1) - Only a few variables are used for calculations.
Solution
To solve the problem, we need to round the purchaseAmount to the nearest multiple of 10. This can be achieved by using integer division and modulus operations. The rounded amount is then subtracted from the starting account balance of 100 dollars to get the final balance. The algorithmic approach involves basic arithmetic operations without the need for complex data structures.