fix: Tree package bug (TheAlgorithms#589)

* add Parent to binary search tree * refactor NIL in all trees * add Successor and Predecessor to * fix: tree package bug * remove dummy variable leaf * Refactoring: remove method; make NIL a sentinel value for 3 trees, and eliminate nil in those implementations. * change the method isRBTree to isRB * fix:remove base struct, separate Node to three different nodes that complete Node Interface; still save NIL, but make it unexported * Add more comments; Move Tree interface to tree_test package for future development. * code tidy * fix typo in comments
pedromsrocha · Jan 15, 2023 · e5658c3 · e5658c3
1 parent 83cff67
commit e5658c3
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Showing 9 changed files with 1,252 additions and 744 deletions.
diff --git a/structure/tree/avl.go b/structure/tree/avl.go
diff --git a/structure/tree/avl_test.go b/structure/tree/avl_test.go
@@ -1,9 +1,11 @@
 package tree_test
 
 import (
-	"testing"
-
 	bt "github.com/TheAlgorithms/Go/structure/tree"
+	"math/rand"
+	"sort"
+	"testing"
+	"time"
 )
 
 func TestAVLPush(t *testing.T) {
@@ -12,51 +14,51 @@ func TestAVLPush(t *testing.T) {
 		tree.Push(5, 4, 3)
 
 		root := tree.Root
-		if root.Key != 4 {
-			t.Errorf("Root should have value = 4, not %v", root.Key)
+		if root.Key() != 4 {
+			t.Errorf("Root should have value = 4, not %v", root.Key())
 		}
-		if root.Height != 2 {
-			t.Errorf("Height of Root should be = 2, not %d", root.Height)
+		if root.Height() != 2 {
+			t.Errorf("Height of Root should be = 2, not %d", root.Height())
 		}
 
-		if root.Left.Key != 3 {
+		if root.Left().Key() != 3 {
 			t.Errorf("Left child should have value = 3")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 5 {
+		if root.Right().Key() != 5 {
 			t.Errorf("Right child should have value = 5")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
-
 	})
+
 	t.Run("LRRotation-Test", func(t *testing.T) {
 		tree := bt.NewAVL[int]()
 		tree.Push(5, 3, 4)
 
 		root := tree.Root
-		if root.Key != 4 {
-			t.Errorf("Root should have value = 4")
+		if root.Key() != 4 {
+			t.Errorf("Root should have value = 4, not %v", root.Key())
 		}
-		if root.Height != 2 {
-			t.Errorf("Height of Root should be = 2")
+		if root.Height() != 2 {
+			t.Errorf("Height of Root should be = 2, not %d", root.Height())
 		}
 
-		if root.Left.Key != 3 {
+		if root.Left().Key() != 3 {
 			t.Errorf("Left child should have value = 3")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 5 {
+		if root.Right().Key() != 5 {
 			t.Errorf("Right child should have value = 5")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
 	})
@@ -68,52 +70,52 @@ func TestAVLPush(t *testing.T) {
 		tree.Push(5)
 
 		root := tree.Root
-		if root.Key != 4 {
-			t.Errorf("Root should have value = 4")
+		if root.Key() != 4 {
+			t.Errorf("Root should have value = 4, not %v", root.Key())
 		}
-		if root.Height != 2 {
-			t.Errorf("Height of Root should be = 2")
+		if root.Height() != 2 {
+			t.Errorf("Height of Root should be = 2, not %d", root.Height())
 		}
 
-		if root.Left.Key != 3 {
+		if root.Left().Key() != 3 {
 			t.Errorf("Left child should have value = 3")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 5 {
+		if root.Right().Key() != 5 {
 			t.Errorf("Right child should have value = 5")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
 	})
-	t.Run("RLRotaion-Test", func(t *testing.T) {
+	t.Run("RLRotation-Test", func(t *testing.T) {
 		tree := bt.NewAVL[int]()
 		tree.Push(3)
 		tree.Push(5)
 		tree.Push(4)
 
 		root := tree.Root
-		if root.Key != 4 {
+		if root.Key() != 4 {
 			t.Errorf("Root should have value = 4")
 		}
-		if root.Height != 2 {
+		if root.Height() != 2 {
 			t.Errorf("Height of Root should be = 2")
 		}
 
-		if root.Left.Key != 3 {
+		if root.Left().Key() != 3 {
 			t.Errorf("Left child should have value = 3")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 5 {
+		if root.Right().Key() != 5 {
 			t.Errorf("Right child should have value = 5")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
 	})
@@ -122,6 +124,9 @@ func TestAVLPush(t *testing.T) {
 func TestAVLDelete(t *testing.T) {
 	t.Run("LLRotation-Test", func(t *testing.T) {
 		tree := bt.NewAVL[int]()
+		if tree.Delete(5) {
+			t.Errorf("There is no node, whose value is 5")
+		}
 
 		tree.Push(5)
 		tree.Push(4)
@@ -137,24 +142,24 @@ func TestAVLDelete(t *testing.T) {
 		}
 
 		root := tree.Root
-		if root.Key != 3 {
+		if root.Key() != 3 {
 			t.Errorf("Root should have value = 3")
 		}
-		if root.Height != 2 {
+		if root.Height() != 2 {
 			t.Errorf("Height of Root should be = 2")
 		}
 
-		if root.Left.Key != 2 {
+		if root.Left().Key() != 2 {
 			t.Errorf("Left child should have value = 2")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 4 {
+		if root.Right().Key() != 4 {
 			t.Errorf("Right child should have value = 5")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
 	})
@@ -164,6 +169,7 @@ func TestAVLDelete(t *testing.T) {
 
 		tree.Push(10)
 		tree.Push(8)
+		tree.Push(8)
 		tree.Push(6)
 		tree.Push(7)
 
@@ -176,24 +182,24 @@ func TestAVLDelete(t *testing.T) {
 		}
 
 		root := tree.Root
-		if root.Key != 7 {
+		if root.Key() != 7 {
 			t.Errorf("Root should have value = 7")
 		}
-		if root.Height != 2 {
+		if root.Height() != 2 {
 			t.Errorf("Height of Root should be = 2")
 		}
 
-		if root.Left.Key != 6 {
+		if root.Left().Key() != 6 {
 			t.Errorf("Left child should have value = 6")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 8 {
+		if root.Right().Key() != 8 {
 			t.Errorf("Right child should have value = 8")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
 
@@ -204,6 +210,7 @@ func TestAVLDelete(t *testing.T) {
 
 		tree.Push(2)
 		tree.Push(3)
+		tree.Push(3)
 		tree.Push(4)
 		tree.Push(5)
 
@@ -216,60 +223,99 @@ func TestAVLDelete(t *testing.T) {
 		}
 
 		root := tree.Root
-		if root.Key != 4 {
+		if root.Key() != 4 {
 			t.Errorf("Root should have value = 4")
 		}
-		if root.Height != 2 {
+		if root.Height() != 2 {
 			t.Errorf("Height of Root should be = 2")
 		}
 
-		if root.Left.Key != 3 {
+		if root.Left().Key() != 3 {
 			t.Errorf("Left child should have value = 3")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 5 {
+		if root.Right().Key() != 5 {
 			t.Errorf("Right child should have value = 5")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
 
 	})
 
-	t.Run("RLRotaion-Test", func(t *testing.T) {
+	t.Run("RLRotation-Test", func(t *testing.T) {
 		tree := bt.NewAVL[int]()
 
 		tree.Push(7)
 		tree.Push(6)
+		tree.Push(6)
 		tree.Push(9)
 		tree.Push(8)
 
 		tree.Delete(6)
 
 		root := tree.Root
-		if root.Key != 8 {
+		if root.Key() != 8 {
 			t.Errorf("Root should have value = 8")
 		}
-		if root.Height != 2 {
+		if root.Height() != 2 {
 			t.Errorf("Height of Root should be = 2")
 		}
 
-		if root.Left.Key != 7 {
+		if root.Left().Key() != 7 {
 			t.Errorf("Left child should have value = 7")
 		}
-		if root.Left.Height != 1 {
+		if root.Left().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Left child should be 1")
 		}
 
-		if root.Right.Key != 9 {
+		if root.Right().Key() != 9 {
 			t.Errorf("Right child should have value = 9")
 		}
-		if root.Right.Height != 1 {
+		if root.Right().(*bt.AVLNode[int]).Height() != 1 {
 			t.Errorf("Height of Right should be 1")
 		}
 
 	})
+
+	t.Run("Random Test", func(t *testing.T) {
+		nums := []int{100, 500, 1000, 10_000}
+		for _, n := range nums {
+			rand.Seed(time.Now().Unix())
+			tree := bt.NewAVL[int]()
+			nums := rand.Perm(n)
+			tree.Push(nums...)
+
+			rets := tree.InOrder()
+			if !sort.IntsAreSorted(rets) {
+				t.Error("Error with Push")
+			}
+
+			if res, ok := tree.Min(); !ok || res != rets[0] {
+				t.Errorf("Error with Min, get %d, want: %d", res, rets[0])
+			}
+
+			if res, ok := tree.Max(); !ok || res != rets[n-1] {
+				t.Errorf("Error with Max, get %d, want: %d", res, rets[n-1])
+			}
+
+			for i := 0; i < n-1; i++ {
+				if ret, ok := tree.Successor(rets[0]); ret != rets[1] || !ok {
+					t.Error("Error with Successor")
+				}
+				if ret, ok := tree.Predecessor(rets[1]); ret != rets[0] || !ok {
+					t.Error("Error with Predecessor")
+				}
+
+				ok := tree.Delete(nums[i])
+				rets = tree.InOrder()
+				if !ok || !sort.IntsAreSorted(rets) {
+					t.Errorf("Error With Delete")
+				}
+			}
+		}
+	})
 }