The longest silence between heartbeats
A service sends a heartbeat every so often. The longest gap between two of them is how long it might have been down without anyone noticing.
- Timestamps arrive in any order and are in seconds.
- The answer is the largest difference between two heartbeats that are next to each other in time.
- Fewer than two heartbeats means no gap at all: return 0.
longestGap(timestamps: list<int>) → 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 longestGap(timestamps []int) int {
}Worked examples
| Call | Result |
|---|---|
longestGap([]int{100, 130, 200, 205}) | 70 |
longestGap([]int{205, 100, 200, 130}) | 70 |
longestGap([]int{10, 20}) | 10 |
longestGap([]int{42}) | 0 |
Hint
Sort first. Without that, "next to each other" means nothing.
Reference solution in Go
func longestGap(timestamps []int) int {
if len(timestamps) < 2 {
return 0
}
s := append([]int{}, timestamps...)
sort.Ints(s)
worst := 0
for i := 1; i < len(s); i++ {
if d := s[i] - s[i-1]; d > worst {
worst = d
}
}
return worst
}