Drop the repeats
A feed sometimes sends the same id twice, and a clean list keeps only the first sighting.
- Keep the first occurrence of each value and drop any that repeat later.
- The relative order of the kept values is untouched.
dedupe(values: list<int>) → list<int>
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 dedupe(values []int) []int {
}Worked examples
| Call | Result |
|---|---|
dedupe([]int{1, 2, 3, 1, 2}) | []int{1, 2, 3} |
dedupe([]int{1, 1, 1}) | []int{1} |
dedupe([]int{}) | []int{} |
dedupe([]int{3, 1, 2, 1, 3}) | []int{3, 1, 2} |
Hint
Carry a set of what you have already seen, and only push a value the first time you meet it.
Reference solution in Go
func dedupe(values []int) []int {
seen := map[int]bool{}
result := []int{}
for _, v := range values {
if !seen[v] {
seen[v] = true
result = append(result, v)
}
}
return result
}