The middle of the list
A dashboard shows a campaign’s typical daily spend, and “typical” is whatever lands in the middle once the days are sorted.
- An odd number of readings: the middle one, once sorted.
- An even number: the average of the two middle ones.
- An empty list has no middle: return zero.
medianOf(values: list<int>) → float
Go 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
func medianOf(values []int) float64 {
}Worked examples
| Call | Result |
|---|---|
medianOf([]int{3, 1, 2}) | 2.0 |
medianOf([]int{1, 2}) | 1.5 |
medianOf([]int{5}) | 5.0 |
medianOf([]int{5, 1, 4, 2}) | 3.0 |
Hint
Sort a copy, not the caller’s list, then look at the middle pair or single value.
Reference solution in Go
func medianOf(values []int) float64 {
xs := append([]int{}, values...)
sort.Ints(xs)
n := len(xs)
if n == 0 {
return 0.0
}
mid := n / 2
if n%2 == 1 {
return float64(xs[mid])
}
return (float64(xs[mid-1]) + float64(xs[mid])) / 2
}