The average so far, after every reading
A quality chart plots not each reading but the average of everything measured up to that point, so a late wobble does not swing the line.
- Every reading is zero or more.
- After each reading, report the mean of every reading so far.
- Drop the fraction — the mean is rounded down to a whole number.
- An empty run of readings gives an empty result.
RunningAverage(readings: list<int>) → list<int>
C# 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
public List<int> RunningAverage(List<int> readings) {
}Worked examples
| Call | Result |
|---|---|
RunningAverage(new List<int> { 10, 20, 30 }) | new List<int> { 10, 15, 20 } |
RunningAverage(new List<int> { 1, 2 }) | new List<int> { 1, 1 } |
RunningAverage(new List<int> { 5 }) | new List<int> { 5 } |
RunningAverage(new List<int> { }) | new List<int> { } |
Hint
Carry the running total and divide by how many readings you have seen. Do not re-add the list each step.
Reference solution in C#
public List<int> RunningAverage(List<int> readings) {
var outList = new List<int>();
int total = 0;
for (int i = 0; i < readings.Count; i++) {
total += readings[i];
outList.Add(total / (i + 1));
}
return outList;
}