func TopoSpec(c gospec.Context) {
c.Specify("Check toposort on linked list", func() {
a := adag{
[]int{1},
[]int{2},
[]int{3},
[]int{4},
[]int{5},
[]int{6},
[]int{},
}
order := algorithm.TopoSort(a)
checkOrder(c, a, order)
})
c.Specify("multi-edges don't mess up toposort", func() {
a := adag{
[]int{1, 1, 1},
[]int{},
}
order := algorithm.TopoSort(a)
checkOrder(c, a, order)
})
c.Specify("Check toposort on a more complicated digraph", func() {
a := adag{
[]int{8, 7, 4}, // 0
[]int{5},
[]int{0},
[]int{9},
[]int{14},
[]int{15}, // 5
[]int{1},
[]int{},
[]int{},
[]int{13},
[]int{3}, // 10
[]int{12},
[]int{18},
[]int{16},
[]int{},
[]int{14}, // 15
[]int{},
[]int{},
[]int{},
[]int{},
[]int{},
}
order := algorithm.TopoSort(a)
checkOrder(c, a, order)
})
c.Specify("A cyclic digraph returns nil", func() {
a := adag{
[]int{8, 7, 4}, // 0
[]int{5},
[]int{0},
[]int{9},
[]int{14},
[]int{15}, // 5
[]int{1},
[]int{},
[]int{20},
[]int{13},
[]int{3}, // 10
[]int{12},
[]int{18},
[]int{16},
[]int{2},
[]int{14}, // 15
[]int{6},
[]int{},
[]int{},
[]int{},
[]int{},
}
order := algorithm.TopoSort(a)
c.Expect(len(order), Equals, 0)
})
}
func order(input []RectObject) []int {
defer func() {
if err := recover(); err != nil {
base.Error().Printf("Failure in sorting: %v", err)
}
}()
var minx, miny int
for _, r := range input {
x, y := r.Pos()
if x < minx {
minx = x
}
if y < miny {
miny = y
}
}
ra := make([]RectObject, len(input))
for i, r := range input {
x, y := r.Pos()
dx, dy := r.Dims()
ra[i] = arog{x - minx + 1, y - miny + 1, dx, dy}
}
mapping := make(map[RectObject]int, len(ra))
for i := range ra {
mapping[ra[i]] = i
}
var e endpointArray
for i := range ra {
e = append(e, endpoint{RectObject: ra[i], first: false})
e = append(e, endpoint{RectObject: ra[i], first: true})
}
sort.Sort(e)
var sweep_pos int
less_func := func(_a, _b interface{}) bool {
a := _a.(RectObject)
b := _b.(RectObject)
ax, ay, ax2, ay2 := firstAndLastPoints(a)
da := ax*ax + ay*ay
da2 := ax2*ax2 + ay2*ay2
w_a := width(a.Dims())
bx, by, bx2, by2 := firstAndLastPoints(b)
db := bx*bx + by*by
db2 := bx2*bx2 + by2*by2
w_b := width(b.Dims())
va := w_b * (w_a*da + (da2-da)*(sweep_pos-pos(ax, ay)))
vb := w_a * (w_b*db + (db2-db)*(sweep_pos-pos(bx, by)))
return va < vb
}
l := llrb.New(less_func)
dag := make(adag, len(ra))
for _, p := range e {
if p.first {
sweep_pos = pos(firstPoint(p.RectObject))
l.ReplaceOrInsert(p.RectObject)
lower := l.LowerBound(p.RectObject)
upper := l.UpperBound(p.RectObject)
if lower != nil {
index := mapping[lower.(RectObject)]
dag[index] = append(dag[index], mapping[p.RectObject])
}
if upper != nil {
index := mapping[p.RectObject]
dag[index] = append(dag[index], mapping[upper.(RectObject)])
}
} else {
l.Delete(p.RectObject)
}
}
return algorithm.TopoSort(dag)
}