Find the shortest interval in a list by *sleeping*

main.go

package main

import (
	"fmt"
	"time"
)

var (
	input = []string{"01h00m", "08h15m", "11h30m", "13h45m", "14h10m", "20h05m"}
)

func main() {
	c := make(chan struct{})

	wg := sync.WaitGroup{}
	wg.Add(len(input))
	for _, s := range input {
		d, err := time.ParseDuration(s)
		if err != nil {
			panic(err)
		}

		go func() {
			time.Sleep(d)
			c <- struct{}{}
			wg.Done()
		}()
	}

	go func() {
		wg.Wait()
		close(c)
	}()

	var last time.Time
	var smol time.Duration
	for range c {
		if last.IsZero() {
			last = time.Now()
			continue
		}

		now := time.Now()
		elapsed := now.Sub(last)
		if int64(smol) == 0 || elapsed < smol {
			smol = elapsed
		}
		last = now
	}

	fmt.Println("smallest interval:", smol)
}