package main

import "fmt"

type segment struct {
	length int64
	data []int64
}

func newSegment(length int64) * segment {
	s := &segment { length , make([]int64,1,8) }
	s.data[0] = length
	return s
}

func (s *segment) insert(from int64 , size int64) (large bool) {
	large = false
	if size <= 0 {
		panic("invalid argment")
	}
	if from > s.length {
		panic("invalid argment")
	}
	if from < 0 {
		panic("invalid argment")
	}
	end := from + size
	if end > s.length {
		panic("invalid argment")
	}
	var i int
	for i=0;i<len(s.data);i++ {
		if from <= s.data[i] {
			break
		}
	}
	if i%2 == 0 {
		if end <= s.data[i] {
			if cap(s.data) < len(s.data)+2 {
				t:=make([]int64, len(s.data)+2)
				copy(t,s.data)
				s.data = t
			} else {
				s.data = s.data[:len(s.data)+2]
			}
			copy(s.data[i+2:],s.data[i:])
			s.data[i] = from
			s.data[i+1] = end
		} else {
			s.data[i] = from
			if end <= s.data[i+1] {
				return
			} else if end <= s.data[i+2] {
				s.data[i+1] = end;
				return
			} else {
				var j int
				for j=i+3;j<len(s.data);j++ {
					if end <= s.data[j] {
						break
					}
				}
				i++
				if j%2 == 0 {
					s.data[i] = end
					i++
				}
				copy(s.data[i:],s.data[j:])
				s.data = s.data[:len(s.data)-(j-i)]
			}
		}
	} else {
		if end <= s.data[i] {
			return
		}
		if end <= s.data[i+1] {
			s.data[i] = end
			return
		}
		var j int
		for j=i+2;j<len(s.data);j++ {
			if end <= s.data[j] {
				break
			}
		}
		if j%2 == 0 {
			s.data[i] = end
			i++
		}
		copy(s.data[i:],s.data[j:])
		s.data = s.data[:len(s.data)-(j-i)]
	}

	return
}

func (s *segment) white() int64 {
	t := s.data[0]
	for i:=2;i<len(s.data);i+=2 {
		t+=s.data[i]-s.data[i-1]
	}
	return t
}

func (s *segment) dump() {
	fmt.Printf("[0,%d) ",s.data[0])
	for i:=2;i<len(s.data);i+=2 {
		fmt.Printf("[%d,%d) ",s.data[i-1],s.data[i])
	}
	fmt.Printf("%d\n",s.white())
}

func (s *segment)ins(from int64,end int64) {
	fmt.Printf("insert %d,%d ",from,end)
	s.insert(from,end-from)
	s.dump()
}

func main() {
	s := newSegment(100)
	s.ins(0,100)
	s.ins(20,50)
	s.ins(30,40)
	s.ins(0,10)
	s.ins(45,60)
	s.ins(70,80)
	s.ins(5,75)
	s.ins(15,75)
}