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Problem with RedBlackTree

P: n/a
I cannot get quite well with the "Insert " method in the RedBlackTree,
could anybody give me a complete implementation of it?

Thanks!

Jun 6 '07 #1
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P: n/a
hi dude:
here's list of C red black tree implementation.
skip the comment if you are not Chinese:)
/**//*-----------------------------------------------------------
RB-Tree
:
1) <<Introduction to algorithm>>
2) <<STL >>
3) sgi-stl stl_tree.h
4) http://epaperpress.com/sortsearch/index.html
5) http://www.ececs.uc.edu/~franco/C321.../redblack.html

(http://www.cppblog.com/converse/)
:
1)
2)
3) ( )
4) ,
5) ,

-------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

typedef int KEY;

enum NODECOLOR
{
BLACK = 0,
RED = 1
};

typedef struct RBTree
{
struct RBTree *parent;
struct RBTree *left, *right;
KEY key;
NODECOLOR color;
}RBTree, *PRBTree;

PRBTree RB_InsertNode(PRBTree root, KEY key);
PRBTree RB_InsertNode_Fixup(PRBTree root, PRBTree z);

PRBTree RB_DeleteNode(PRBTree root, KEY key);
PRBTree RB_DeleteNode_Fixup(PRBTree root, PRBTree z);

PRBTree Find_Node(PRBTree root, KEY key);
void Left_Rotate(PRBTree A, PRBTree& root);
void Right_Rotate(PRBTree A, PRBTree& root);
void Mid_Visit(PRBTree T);
void Mid_DeleteTree(PRBTree T);
void Print_Node(PRBTree node);

/**//*-----------------------------------------------------------
| A B
| / \ == / \
| a B A y
| / \ / \
| b y a b
-----------------------------------------------------------*/
void Left_Rotate(PRBTree A, PRBTree& root)
{
PRBTree B;
B = A->right;

if (NULL == B)
return;

A->right = B->left;
if (NULL != B->left)
B->left->parent = A;
B->parent = A->parent;
// A->parent = NULL
if (A == root)
{
root = B;
}
else if (A == A->parent->left)
{
A->parent->left = B;
}
else
{
A->parent->right = B;
}
B->left = A;
A->parent = B;
}

/**//*-----------------------------------------------------------
| A B
| / \ / \
| B y == a A
| / \ / \
|a b b y
-----------------------------------------------------------*/
void Right_Rotate(PRBTree A, PRBTree& root)
{
PRBTree B;
B = A->left;

if (NULL == B)
return;

A->left = B->right;
if (NULL != B->right)
B->right->parent = A;
B->parent = A->parent;
// A->parent = NULL
if (A == root)
{
root = B;
}
else if (A == A->parent->left)
{
A->parent->left = B;
}
else
{
A->parent->right = B;
}
A->parent = B;
B->right = A;
}

/**//*-----------------------------------------------------------
| : key
| : root, key
| : , NULL
-------------------------------------------------------------*/
PRBTree Find_Node(PRBTree root, KEY key)
{
PRBTree x;

// key node
x = root;
do
{
if (key == x->key)
break;
if (key < x->key)
{
if (NULL != x->left)
x = x->left;
else
break;
}
else
{
if (NULL != x->right)
x = x->right;
else
break;
}
} while (NULL != x);

return x;
}

/**//*-----------------------------------------------------------
| : key
| : root, key
| : root
-------------------------------------------------------------*/
PRBTree RB_InsertNode(PRBTree root, KEY key)
{
PRBTree x, y;

PRBTree z;
if (NULL == (z = (PRBTree)malloc(sizeof(RBTree))))
{
printf("Memory alloc error\n");
return NULL;
}
z->key = key;

// z
x = root, y = NULL;
while (NULL != x)
{
y = x;
if (z->key < x->key)
{
if (NULL != x->left)
{
x = x->left;
}
else
{
break;
}
}
else
{
if (NULL != x->right)
{
x = x->right;
}
else
{
break;
}
}
}

// z
z->parent = y;
if (NULL == y)
{
root = z;
}
else
{
if (z->key < y->key)
y->left = z;
else
y->right = z;
}
// z red red
z->left = z->right = NULL;
z->color = RED;

//
return RB_InsertNode_Fixup(root, z);
}

/**//*-----------------------------------------------------------
| : key
| : root, z
| : root
-------------------------------------------------------------*/
PRBTree RB_InsertNode_Fixup(PRBTree root, PRBTree z)
{
PRBTree y;
while (root != z && RED == z->parent->color) // z
red
{
if (z->parent == z->parent->parent->left) //

{
y = z->parent->parent->right; // y z

if (NULL != y && RED == y->color) //
red
{
z->parent->color = BLACK; // z
B
y->color =
BLACK; // z B
z->parent->parent->color = RED; // z
B
z = z->parent-
>parent; // z
}

else //
b
{
if (z == z->parent->right) //

{
z = z->parent;
Left_Rotate(z, root);
}
z->parent->color = BLACK; //
B
z->parent->parent->color = RED; //
R
Right_Rotate(z->parent->parent, root);
}
}

else //

{
y = z->parent->parent->left; // y z

if (NULL != y && RED == y->color) // y
red
{
z->parent->color = BLACK; //
B
y->color =
BLACK; // B
z->parent->parent->color = RED; //
R
z = z->parent-
>parent; // z
}

else //
y B
{
if (z == z->parent->left) //

{
z = z->parent;
Right_Rotate(z, root);
}
z->parent->color = BLACK; //
B
z->parent->parent->color = RED; //
RED
Left_Rotate(z->parent->parent, root);
}
}
} // while(RED == z->parent->color)

// B
root->color = BLACK;

return root;
}

/**//*-----------------------------------------------------------
| : key
| : root, key
| : root
-------------------------------------------------------------*/
PRBTree RB_DeleteNode(PRBTree root, KEY key)
{
PRBTree x, y, z, x_parent;

z = Find_Node(root, key);
if (NULL == z)
return root;

// z ,y == z
// ,y z
if (NULL == z->left || NULL == z->right)
y = z;
else
{
y = z->right;
while (NULL != y->left)
y = y->left;
}

// x y , NULL
if (NULL != y->left)
x = y->left;
else
x = y->right;

// x y
if (NULL != x)
x->parent = y->parent;
if (NULL == y->parent)
root = x;
else if (y == y->parent->left)
y->parent->left = x;
else
y->parent->right = x;

// y key z , y
if (y != z)
{
z->key = y->key;
}

// y B,
if (BLACK == y->color && NULL != x)
RB_DeleteNode_Fixup(root, x);

free(y);

return root;
}

/**//*-----------------------------------------------------------
| : key
| : root, x
| : root
-------------------------------------------------------------*/
PRBTree RB_DeleteNode_Fixup(PRBTree root, PRBTree x)
{
PRBTree w;

while (x != root && BLACK == x->color)
{
if (x == x->parent-
>left) //
x
{
w = x->parent-
>right; //
w x

if (NULL == w)
continue;

if (RED == w-
>color) //
w
{
w->color = BLACK;
x->parent->color = RED;
Left_Rotate(x->parent, root);
w = x->parent->right;
}
if (NULL != w->left && BLACK == w->left->color &&
NULL != w->right && BLACK == w->right->color)
{
w->color = RED;
x = x->parent;
}
else
{
if (NULL != w->right && BLACK == w->right->color)
{
w->left->color = BLACK;
w->color = RED;
Right_Rotate(w, root);
w = x->parent->right;
}

w->color = x->parent->color;
x->parent->color = BLACK;
w->right->color = BLACK;
Left_Rotate(x->parent, root);
x = root;
}
}
else
{
w = x->parent->left;
if (NULL == w)
continue;
if (RED == w->color)
{
w->color = BLACK;
x->parent->color = RED;
Left_Rotate(x->parent, root);
w = x->parent->left;
}
if (NULL != w->left && BLACK == w->left->color &&
NULL != w->right && BLACK == w->right->color)
{
w->color = RED;
x = x->parent;
}
else
{
if (NULL != w->left && BLACK == w->left->color)
{
w->right->color = BLACK;
w->color = RED;
Left_Rotate(w, root);
w = x->parent->left;
}

w->color = x->parent->color;
x->parent->color = BLACK;
w->left->color = BLACK;
Right_Rotate(x->parent, root);
x = root;
}
}
}

x->color = BLACK;

return root;
}

void Print_Node(PRBTree node)
{
char* color[] = {"BLACK", "RED"};
printf("Key = %d,\tcolor = %s", node->key, color[node->color]);
if (NULL != node->parent)
printf(",\tparent = %d", node->parent->key);
if (NULL != node->left)
printf(",\tleft = %d", node->left->key);
if (NULL != node->right)
printf(",\tright = %d", node->right->key);
printf("\n");
}

//
void Mid_Visit(PRBTree T)
{
if (NULL != T)
{
if (NULL != T->left)
Mid_Visit(T->left);
Print_Node(T);
if (NULL != T->right)
Mid_Visit(T->right);
}
}

//
void Mid_DeleteTree(PRBTree T)
{
if (NULL != T)
{
if (NULL != T->left)
Mid_DeleteTree(T->left);
PRBTree temp = T->right;
free(T);
T = NULL;
if (NULL != temp)
Mid_DeleteTree(temp);
}
}

void Create_New_Array(int array[], int length)
{
for (int i = 0; i < length; i++)
{
array[i] = rand() % 256;
}
}

int main(int argc, char *argv[])
{
//int array[10] = {80, 116, 81, 205, 82, 68, 151, 20, 109, 100};
int array[10];
srand(time(NULL));
Create_New_Array(array, 10);
PRBTree root = NULL;
int i;
for (i = 0; i < 10; i++)
{
root = RB_InsertNode(root, array[i]);
}

Mid_Visit(root);

//
int index = rand() % 10;
printf("delete node %d\n", array[index]);
root = RB_DeleteNode(root, array[index]);
Mid_Visit(root);

//
Mid_DeleteTree(root);

return 0;
}
On Jun 6, 11:34 am, Evil_man <Evilcheng...@gmail.comwrote:
I cannot get quite well with the "Insert " method in the RedBlackTree,
could anybody give me a complete implementation of it?

Thanks!

Jun 6 '07 #2

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