package main
import (
"fmt"
"math/rand"
"sort"
"time"
)
// generateNonOverlappingRandomRangescreates numRanges random (start,end) pairs
// that are guaranteed to be non-overlapping.
//
// 1. Generate unique random points (chaotic order)
// 2. Sort them
// 3. Pair adjacent points → automatically non-overlapping
func generateNonOverlappingRandomRanges(begin, end, numRanges int) [][2]int {
count := numRanges * 2
rand.Seed(time.Now().UnixNano())
// ------------------------------------------------------------
// Generate unique random points in [begin, end)
// The random numbers are chaotic and NOT sorted
// ------------------------------------------------------------
pointsSet := make(map[int]struct{})
for len(pointsSet) < count {
r := begin + rand.Intn(end-begin)
pointsSet[r] = struct{}{}
}
// Convert map keys → slice
points := make([]int, 0, count)
for p := range pointsSet {
points = append(points, p)
}
// ------------------------------------------------------------
// Sort the points
// Only AFTER sorting do the ranges become increasing
// and automatically non-overlapping
// ------------------------------------------------------------
sort.Ints(points)
// ------------------------------------------------------------
// Pair adjacent sorted points into (start, end) ranges
// ------------------------------------------------------------
ranges := make([][2]int, 0, numRanges)
for i := 0; i < len(points); i += 2 {
ranges = append(ranges, [2]int{points[i], points[i + 1]})
}
return ranges
}
func main() {
start := 1
end := 500
numRanges := 8
ranges := generateNonOverlappingRandomRanges(start, end, numRanges)
for _, r := range ranges {
fmt.Printf("(%d, %d)\n", r[0], r[1])
}
}
/*
run:
(71, 75)
(92, 97)
(101, 144)
(145, 203)
(240, 288)
(345, 402)
(406, 440)
(447, 481)
*/
