Total hours a machine ran
A machine records operations as start and end minutes past midnight. Convert the whole running total into whole hours.
- Each operation adds end minus start minutes.
- Total is reported in whole hours, truncated down.
- Operations never cross midnight and every end is after its start.
runHours(operations: list<Operation>) → int
Java needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
int runHours(List<Operation> operations) {
}Worked examples
| Call | Result |
|---|---|
runHours(Main.<Operation>ls(new Operation(0, 60), new Operation(600, 900))) | 6 |
runHours(Main.<Operation>ls(new Operation(540, 600))) | 1 |
runHours(Main.<Operation>ls()) | 0 |
runHours(Main.<Operation>ls(new Operation(0, 30))) | 0 |
Hint
Sum the minute spans, then integer-divide the total by sixty.
Reference solution in Java
int runHours(List<Operation> operations) {
int total = 0;
for (Operation o : operations) total += o.end - o.start;
return total / 60;
}