红黑树实现文件C语言

  这个东西,保证了树的深度很低,而且旋转的次数很少.较同类的AVL树有了很大的提高.但是实现起来,并不简单.

  好吧,继续我的习惯,代码说明问题.

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/* RedBlackTree.c -- 红黑树实现文件 */ #include "RedBlackTree.h" /* 全局变量引用 */ extern Node * NullNode ; extern Node * Current, * Sibling, * Parent, * GrParent, * GrGrParent ; /* 局部函数声明 */ static Node * singleRotateWithLeft (Node * const parent) ; static Node * singleRotateWithRight (Node * const parent) ; static Node * rotate (Node * const parent, const Item item) ; static void handleReorient (RedBlackTree * const prbt, const Item item) ; static void changeColor (void) ; static void traversal (const Node * const pn, void (* pfun) (const Node * const pn)) ; static void release (Node * const pn) ; /* 接口函数定义 */ /* (*prbt) -> root -> right is the real root instead of (*prbt) -> root. */ BOOL Create_R (RedBlackTree * const prbt) { NullNode = (Node *) malloc (sizeof (Node)) ; if (NULL == NullNode) return FALSE ; *prbt = (struct redBlackTree *) malloc (sizeof (struct redBlackTree)) ; if (NULL == *prbt) { free (NullNode) ; NullNode = NULL ; return FALSE ; } (*prbt) -> root = (Node *) malloc (sizeof (Node)) ; if (NULL == (*prbt) -> root) { free (NullNode) ; NullNode = NULL ; free (*prbt) ; } NullNode -> item = INFINITY ; NullNode -> left = NullNode -> right = NullNode ; NullNode -> color = Black ; (*prbt) -> root -> item = NEGATIVE_INFINITY ; (*prbt) -> root -> left = (*prbt) -> root -> right = NullNode ; (*prbt) -> root -> color = Black ; (*prbt) -> current = 0 ; return TRUE ; } BOOL IsEmpty_R (const RedBlackTree * const prbt) { if (0 == (*prbt) -> current) return TRUE ; else return FALSE ; } BOOL Insert_R (RedBlackTree * const prbt, const Item item) { Node * newNode ; GrParent = Parent = Current = (*prbt) -> root ; NullNode -> item = item ; while (Current -> item != item) { GrGrParent = GrParent ; GrParent = Parent ; Parent = Current ; if (item < Current -> item) Current = Current -> left ; else Current = Current -> right ; if (Red == Current -> left -> color && Red == Current -> right -> color) handleReorient (prbt, item) ; } if (Current != NullNode) return FALSE ; newNode = (Node *) malloc (sizeof (Node)) ; if (NULL == newNode) return FALSE ; newNode -> item = item ; newNode -> left = newNode -> right = NullNode ; if (item < Parent -> item) Parent -> left = newNode ; else Parent -> right = newNode ; Current = newNode ; handleReorient (prbt, item) ; (*prbt) -> current++ ; return TRUE ; } /* The central idea is go to delete a red leaf. */ BOOL Delete_R (RedBlackTree * const prbt, const Item item) { BOOL found = FALSE ; Node * record ; Item scapegoat ; int temp ; if (IsEmpty_R (prbt)) return FALSE ; Current = (*prbt) -> root ; /* First, look for it. */ while (Current != NullNode) { if (item == Current -> item) { found = TRUE ; record = Current ; break ; } else if (item < Current -> item) { Parent = Current ; Current = Current -> left ; } else { Parent = Current ; Current = Current -> right ; } } /* If not found. */ if (FALSE == found) return FALSE ; if (Current -> right != NullNode) { Parent = Current ; Current = Parent -> right ; scapegoat = Current -> item ; /* Without optimizing it. */ while (Current -> left != NullNode) { Parent = Current ; Current = Current -> left ; scapegoat = Current -> item ; } /* Make it be a lead. */ if (Current -> right != NullNode) { temp = Current -> color ; Current -> color = Current -> right -> color ; Current -> right -> color = temp ; Parent -> left = singleRotateWithRight (Current) ; } } else if (Current -> left != NullNode) { Parent = Current ; Current = Parent -> left ; scapegoat = Current -> item ; while (Current -> right != NullNode) { Parent = Current ; Current = Current -> right ; scapegoat = Current -> item ; } if (Current -> left != NullNode) { temp = Current -> color ; Current -> color = Current -> left -> color ; Current -> left -> color = temp ; Parent -> right = singleRotateWithLeft (Current) ; } } /* If Current is a leaf. */ else { /* If current is a red leaf. */ if (Red == Current -> color) { if (Current == Parent -> left) Parent -> left = NullNode ; else Parent -> right = NullNode ; free (Current) ; (*prbt) -> current-- ; return TRUE ; } else scapegoat = Current -> item ; } /* Next hasn't be integrated. */ (*prbt) -> root -> color = Red ; Current = (*prbt) -> root ; /* Make sure NullNode -> item hasn't appear in the tree. */ NullNode -> item = (*prbt) -> root -> item ; /* Core loop. */ while (Current -> item != scapegoat) { if (scapegoat < Current -> item) { /* Updata node. */ GrParent = Parent ; Parent = Current ; Current = Parent -> left ; Sibling = Parent -> right ; /* If Current has a leaf at least. */ if (Red == Current -> left -> color || Red == Current -> right -> color) { if (scapegoat < Current -> item) { /* If Current drops onto a black node. */ if (Black == Current -> left -> color) { Current -> color = Red ; Current -> right -> color = Black ; Parent -> left = singleRotateWithRight (Current) ; } /* If Current drops on to a red node, update node and continue. */ else { GrParent = Parent ; Parent = Current ; Current = Parent -> left ; Sibling = Parent -> right ; continue ; } } else { /* If Current drops onto a black node. */ if (Black == Current -> right -> color) { Current -> color = Red ; Current -> left -> color = Black ; Parent -> left = singleRotateWithLeft (Current) ; } /* If Current drops on to a red node, update node and continue. */ else { GrParent = Parent ; Parent = Current ; Current = Parent -> right ; Sibling = Parent -> left ; continue ; } } } /* If Current has two black children. */ if (Black == Current -> left -> color && Black == Current -> right -> color) { /* If Sibling's left child is red. */ if (Red == Sibling -> left -> color) { Parent -> right = singleRotateWithLeft (Sibling) ; Parent -> color = Black ; Current -> color = Red ; if (Parent == GrParent -> left) GrParent -> left = singleRotateWithRight (Parent) ; else GrParent -> right = singleRotateWithRight (Parent) ; } /* If Sibling's right child is red. */ else if (Red == Sibling -> right -> color) { Parent -> color = Black ; Sibling -> right -> color = Black ; Sibling -> color = Red ; Current -> color = Red ; if (Parent == GrParent -> left) GrParent -> left = singleRotateWithRight (Parent) ; else GrParent -> right = singleRotateWithRight (Parent) ; } /* If Sibling has two black children. */ else changeColor () ; } } /* The circumstances of whirling has a little strange. */ else { GrParent = Parent ; Parent = Current ; Current = Parent -> right ; Sibling = Parent -> left ; if (Red == Current -> left -> color || Red == Current -> right -> color) { if (scapegoat < Current -> item) { if (Black == Current -> left -> color) { Current -> color = Red ; Current -> right -> color = Black ; Parent -> right = singleRotateWithRight (Current) ; } else { GrParent = Parent ; Parent = Current ; Current = Parent -> left ; Sibling = Parent -> right ; continue ; } } else { if (Black == Current -> right -> color) { Current -> color = Red ; Current -> left -> color = Black ; Parent -> left = singleRotateWithLeft (Current) ; } else { GrParent = Parent ; Parent = Current ; Current = Parent -> right ; Sibling = Parent -> left ; continue ; } } } if (Black == Current -> left -> color && Black == Current -> right -> color) { if (Red == Sibling -> left -> color) { Parent -> color = Black ; Sibling -> left -> color = Black ; Sibling -> color = Red ; Current -> color = Red ; if (Parent == GrParent -> left) GrParent -> left = singleRotateWithLeft (Parent) ; else GrParent -> right = singleRotateWithLeft (Parent) ; } else if (Red == Sibling -> right -> color) { Parent -> left = singleRotateWithRight (Sibling) ; Parent -> color = Black ; Current -> color = Red ; if (Parent == GrParent -> left) GrParent -> left = singleRotateWithLeft (Parent) ; else GrParent -> right = singleRotateWithLeft (Parent) ; } else { changeColor () ; if (Red == NullNode -> color) { putchar ('/a') ; NullNode -> color = Black ; } } } } } /* Replace. */ record -> item = scapegoat ; if (scapegoat == Parent -> left -> item) Parent -> left = NullNode ; else Parent -> right = NullNode ; free (Current) ; (*prbt) -> root -> color = Black ; (*prbt) -> root -> right -> color = Black ; (*prbt) -> current-- ; return TRUE ; } void Traversal_R (const RedBlackTree * const prbt, void (* pfun) (const Node * const pn)) { traversal ((*prbt) -> root -> right, pfun) ; putchar ('/n') ; } void Release_R (const RedBlackTree * const prbt) { release ((*prbt) -> root -> right) ; free ((*prbt) -> root) ; free (*prbt) ; free (NullNode) ; } /* 局部函数定义 */ /* child will become the new root of the subtree. */ static Node * singleRotateWithLeft (Node * const parent) { Node * child ; child = parent -> left ; parent -> left = child -> right ; child -> right = parent ; return child ; } static Node * singleRotateWithRight (Node * const parent) { Node * child ; child = parent -> right ; parent -> right = child -> left ; child -> left = parent ; return child ; } static Node * rotate (Node * const parent, const Item item) { if (item < parent -> item) { return parent -> left = item < parent -> left -> item ? singleRotateWithLeft (parent -> left) : singleRotateWithRight (parent -> left) ; } else { return parent -> right = item < parent -> right -> item ? singleRotateWithLeft (parent -> right) : singleRotateWithRight (parent -> right) ; } } static void handleReorient (RedBlackTree * const prbt, const Item item) { Current -> color = Red ; Current -> left -> color = Current -> right -> color = Black ; if (Red == Parent -> color) { GrParent -> color = Red ; if ((item < GrParent -> item) != (item < Parent -> item)) Parent = rotate (GrParent, item) ; Current = rotate (GrGrParent, item) ; Current -> color = Black ; } (*prbt) -> root -> right -> color = Black ; } /* Won't change NullNode's color. */ static void changeColor (void) { if (Parent -> left != NullNode) Parent -> left -> color = Red ; Parent -> color = Black ; Parent -> right -> color = Red ; } static void traversal (const Node * const pn, void (* pfun) (const Node * const pn)) { if (pn != NullNode) { traversal (pn -> left, pfun) ; (* pfun) (pn) ; traversal (pn -> right, pfun) ; } } static void release (Node * const pn) { if (pn != NullNode) { release (pn -> left) ; release (pn -> right) ; free (pn) ; } }