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InOrderTraverse fixes
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- Fix build (missing import and trivial wrong symbol)
- Pass end of interval along with start of interval to VisitFunc
- Make VisitFunc pass the interval before the value to match Update prototype
- Add tests
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@gilbsgilbs
gilbsgilbs committed Dec 2, 2024
1 parent 5ab740a commit 17e6227
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Showing 2 changed files with 254 additions and 13 deletions.
30 changes: 17 additions & 13 deletions interval/search.go
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,9 @@
package interval

import (
"errors"
)

// Find returns the value which interval key exactly matches with the given start and end interval.
// It returns true as the second return value if an exaclty matching interval key is found in the tree;
// otherwise, false.
Expand Down Expand Up @@ -484,13 +488,13 @@ func maxEnd[V, T any](n *node[V, T], searchEnd T, cmp CmpFunc[T], visit func(*no
var StopTraversal = errors.New("stop tree traversal")

// VisitFunc is called on all values. Returning non-nil error will stop iteration.
// If the returned error is [StopTraversal], the iteration is interrupted, but no error is returned to the caller.
type VisitFunc[V, T any] func(V, T) error
// If the returned error is [StopTraversal], the iteration is interrupted, but no error is returned to the caller.
type VisitFunc[V, T any] func(T, T, V) error

// InOrderTraverse traverses the tree in order and applies VisitFunc to each node. It's safe for concurrent use. To prevent deadlock, avoid calling other tree methods within visitFunc.
func (st *SearchTree[V, T]) InOrderTraverse(visitFunc VisitFunc[V, T]) error {
tree.mu.RLock()
defer tree.mu.RUnlock()
st.mu.RLock()
defer st.mu.RUnlock()

var inOrder func(n *node[V, T]) error
inOrder = func(n *node[V, T]) error {
Expand All @@ -504,7 +508,7 @@ func (st *SearchTree[V, T]) InOrderTraverse(visitFunc VisitFunc[V, T]) error {
}

// Visit current node
err := visitFunc(n.Interval.Val, n.Interval.Start)
err := visitFunc(n.Interval.Start, n.Interval.End, n.Interval.Val)
if err != nil {
return err
}
Expand All @@ -513,18 +517,18 @@ func (st *SearchTree[V, T]) InOrderTraverse(visitFunc VisitFunc[V, T]) error {
return inOrder(n.Right)
}

err := inOrder(tree.root)
err := inOrder(st.root)
// Do not percolate StopTraversal error to the caller.
if errors.Is(err, StopTraversal) {
return nil
return nil
}
return err
}

// InOrderTraverse traverses the tree in order and applies VisitFunc to each node. It's safe for concurrent use. To prevent deadlock, avoid calling other tree methods within visitFunc.
func (st *MultiValueSearchTree[V, T]) InOrderTraverse(visitFunc VisitFunc[V, T]) error {
tree.mu.RLock()
defer tree.mu.RUnlock()
func (st *MultiValueSearchTree[V, T]) InOrderTraverse(visitFunc VisitFunc[[]V, T]) error {
st.mu.RLock()
defer st.mu.RUnlock()

var inOrder func(n *node[V, T]) error
inOrder = func(n *node[V, T]) error {
Expand All @@ -538,7 +542,7 @@ func (st *MultiValueSearchTree[V, T]) InOrderTraverse(visitFunc VisitFunc[V, T])
}

// Visit current node
err := visitFunc(n.Interval.Vals, n.Interval.Start)
err := visitFunc(n.Interval.Start, n.Interval.End, n.Interval.Vals)
if err != nil {
return err
}
Expand All @@ -547,10 +551,10 @@ func (st *MultiValueSearchTree[V, T]) InOrderTraverse(visitFunc VisitFunc[V, T])
return inOrder(n.Right)
}

err := inOrder(tree.root)
err := inOrder(st.root)
// Do not percolate StopTraversal error to the caller.
if errors.Is(err, StopTraversal) {
return nil
return nil
}
return err
}
237 changes: 237 additions & 0 deletions interval/search_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -587,6 +587,124 @@ func TestSearchTree_Select(t *testing.T) {
}
}

func TestSearchTree_InOrderTraverse(t *testing.T) {
type insert struct {
start int
end int
val string
}
tests := []struct {
name string
inserts []insert
expectedVisits []string
}{
{
name: "empty interval",
inserts: []insert{},
expectedVisits: []string{},
},
{
name: "single interval",
inserts: []insert{
{start: 1, end: 10, val: "node1"},
},
expectedVisits: []string{"node1"},
},
{
name: "multiple intervals",
inserts: []insert{
{start: 1, end: 10, val: "node1"},
{start: 5, end: 15, val: "node2"},
{start: 10, end: 20, val: "node3"},
{start: 15, end: 25, val: "node4"},
{start: 20, end: 30, val: "node5"},
},
expectedVisits: []string{"node1", "node2", "node3", "node4", "node5"},
},
{
name: "multiple intervals with same end",
inserts: []insert{
{start: 1, end: 10, val: "node1"},
{start: 5, end: 15, val: "node2"},
{start: 10, end: 20, val: "node3"},
{start: 15, end: 25, val: "node4"},
{start: 20, end: 30, val: "node5"},
{start: 25, end: 30, val: "node6"},
},
expectedVisits: []string{"node1", "node2", "node3", "node4", "node5", "node6"},
},
{
name: "multiple intervals with same end and same start",
inserts: []insert{
{start: 20, end: 30, val: "node5"},
{start: 25, end: 30, val: "node6"},
{start: 15, end: 30, val: "node7"},
},
expectedVisits: []string{"node7", "node5", "node6"},
},
{
name: "interval spanning entire range",
inserts: []insert{
{start: 1, end: 5, val: "node1"},
{start: 5, end: 10, val: "node2"},
{start: 10, end: 20, val: "node3"},
{start: 0, end: 30, val: "node4"},
},
expectedVisits: []string{"node4", "node1", "node2", "node3"},
},
}

for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
st := NewSearchTree[string](func(x, y int) int { return x - y })

for _, insert := range tc.inserts {
st.Insert(insert.start, insert.end, insert.val)
}

got := []string{}

err := st.InOrderTraverse(func(start, end int, node string) error {
got = append(got, node)
return nil
})
if err != nil {
t.Fatalf("st.InOrderTraverse(): error %v", err)
}

if !reflect.DeepEqual(got, tc.expectedVisits) {
t.Errorf("st.InOderTraverse(): got unexpected value %v; want %v", got, tc.expectedVisits)
}
})
}

t.Run("stop traversal", func(t *testing.T) {
st := NewSearchTree[string](func(x, y int) int { return x - y })
st.Insert(17, 19, "node1")
st.Insert(5, 8, "node2")
st.Insert(21, 24, "node3")
st.Insert(4, 8, "node4")

want := []string{"node4", "node2", "node1"}
got := []string{}
err := st.InOrderTraverse(func(start, end int, node string) error {
got = append(got, node)
if node == "node1" {
return StopTraversal
}
return nil
})

if err != nil {
t.Fatalf("st.InOrderTraverse(): error %v", err)
}

if !reflect.DeepEqual(got, want) {
t.Errorf("st.InOderTraverse(): got unexpected value %v; want %v", got, want)
}
})
}

func TestMultiValueSearchTree_AnyIntersection(t *testing.T) {
st := NewMultiValueSearchTree[string](func(x, y int) int { return x - y })
defer mustBeValidTree(t, st.root)
Expand Down Expand Up @@ -1115,3 +1233,122 @@ func TestMultiValueSearchTree_MaxEnd(t *testing.T) {
}

}

func TestMultiValueSearchTree_InOrderTraverse(t *testing.T) {
type insert struct {
start int
end int
val string
}
tests := []struct {
name string
inserts []insert
expectedVisits [][]string
}{
{
name: "empty interval",
inserts: []insert{},
expectedVisits: [][]string{},
},
{
name: "single interval",
inserts: []insert{
{start: 1, end: 10, val: "node1"},
{start: 1, end: 10, val: "node2"},
},
expectedVisits: [][]string{{"node1", "node2"}},
},
{
name: "multiple intervals",
inserts: []insert{
{start: 1, end: 10, val: "node1"},
{start: 5, end: 15, val: "node2"},
{start: 10, end: 20, val: "node3"},
{start: 15, end: 25, val: "node4"},
{start: 20, end: 30, val: "node5"},
},
expectedVisits: [][]string{{"node1"}, {"node2"}, {"node3"}, {"node4"}, {"node5"}},
},
{
name: "multiple intervals with same end",
inserts: []insert{
{start: 1, end: 10, val: "node1"},
{start: 5, end: 15, val: "node2"},
{start: 10, end: 20, val: "node3"},
{start: 15, end: 25, val: "node4"},
{start: 20, end: 30, val: "node5"},
{start: 25, end: 30, val: "node6"},
},
expectedVisits: [][]string{{"node1"}, {"node2"}, {"node3"}, {"node4"}, {"node5"}, {"node6"}},
},
{
name: "multiple intervals with same end and same start",
inserts: []insert{
{start: 20, end: 30, val: "node5"},
{start: 25, end: 30, val: "node6"},
{start: 15, end: 30, val: "node7"},
},
expectedVisits: [][]string{{"node7"}, {"node5"}, {"node6"}},
},
{
name: "interval spanning entire range",
inserts: []insert{
{start: 1, end: 5, val: "node1"},
{start: 5, end: 10, val: "node2"},
{start: 10, end: 20, val: "node3"},
{start: 0, end: 30, val: "node4"},
},
expectedVisits: [][]string{{"node4"}, {"node1"}, {"node2"}, {"node3"}},
},
}

for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
st := NewMultiValueSearchTree[string](func(x, y int) int { return x - y })

for _, insert := range tc.inserts {
st.Insert(insert.start, insert.end, insert.val)
}

got := [][]string{}

err := st.InOrderTraverse(func(start, end int, node []string) error {
got = append(got, node)
return nil
})
if err != nil {
t.Fatalf("st.InOrderTraverse(): error %v", err)
}

if !reflect.DeepEqual(got, tc.expectedVisits) {
t.Errorf("st.InOderTraverse(): got unexpected value %v; want %v", got, tc.expectedVisits)
}
})
}

t.Run("stop traversal", func(t *testing.T) {
st := NewMultiValueSearchTree[string](func(x, y int) int { return x - y })
st.Insert(17, 19, "node1")
st.Insert(5, 8, "node2")
st.Insert(21, 24, "node3")
st.Insert(4, 8, "node4")

want := [][]string{{"node4"}, {"node2"}, {"node1"}}
got := [][]string{}
err := st.InOrderTraverse(func(start, end int, node []string) error {
got = append(got, node)
if node[0] == "node1" {
return StopTraversal
}
return nil
})

if err != nil {
t.Fatalf("st.InOrderTraverse(): error %v", err)
}

if !reflect.DeepEqual(got, want) {
t.Errorf("st.InOderTraverse(): got unexpected value %v; want %v", got, want)
}
})
}

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