基于visual Studio2013解决算法导论之048红黑树



题目

红黑树

解决代码及点评

// 红黑树.cpp : 定义控制台应用程序的入口点。
//

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

typedef int key_t;
typedef int data_t;

typedef enum color_t
{
	RED = 0,
	BLACK = 1
}color_t;

typedef struct rb_node_t
{
	struct rb_node_t *left, *right, *parent;
	key_t key;
	data_t data;
	color_t color;
}rb_node_t;

/* forward declaration */
rb_node_t* rb_insert(key_t key, data_t data, rb_node_t* root);
rb_node_t* rb_search(key_t key, rb_node_t* root);
rb_node_t* rb_erase(key_t key, rb_node_t* root);

int main()
{
	int i, count = 90;
	key_t key;
	rb_node_t* root = NULL, *node = NULL;

	//srand(time(NULL));
	for (i = 1; i < count; ++i)
	{
		key = rand() % count;
		if ((root = rb_insert(key, i, root)))
		{
			printf("[i = %d] insert key %d success!\n", i, key);
		}
		else
		{
			printf("[i = %d] insert key %d error!\n", i, key);
			exit(-1);
		}

		if ((node = rb_search(key, root)))
		{
			printf("[i = %d] search key %d success!\n", i, key);
		}
		else
		{
			printf("[i = %d] search key %d error!\n", i, key);
			exit(-1);
		}
		if (!(i % 10))
		{
			if ((root = rb_erase(key, root)))
			{
				printf("[i = %d] erase key %d success\n", i, key);
			}
			else
			{
				printf("[i = %d] erase key %d error\n", i, key);
			}
		}
	}

	return 0;
}

static rb_node_t* rb_new_node(key_t key, data_t data)
{
	rb_node_t *node = (rb_node_t*)malloc(sizeof(struct rb_node_t));

	if (!node)
	{
		printf("malloc error!\n");
		exit(-1);
	}
	node->key = key, node->data = data;

	return node;
}

/*-----------------------------------------------------------
|   node           right
|   / \    ==>     / \
|   a  right     node  y
|       / \           / \
|       b  y         a   b
-----------------------------------------------------------*/
static rb_node_t* rb_rotate_left(rb_node_t* node, rb_node_t* root)
{
	rb_node_t* right = node->right;

	if ((node->right = right->left))
	{
		right->left->parent = node;
	}
	right->left = node;

	if ((right->parent = node->parent))
	{
		if (node == node->parent->right)
		{
			node->parent->right = right;
		}
		else
		{
			node->parent->left = right;
		}
	}
	else
	{
		root = right;
	}
	node->parent = right;

	return root;
}

/*-----------------------------------------------------------
|       node           left
|       / \            / \
|    left  y   ==>    a   node
|   / \               / \
|  a   b             b   y
-----------------------------------------------------------*/
static rb_node_t* rb_rotate_right(rb_node_t* node, rb_node_t* root)
{
	rb_node_t* left = node->left;

	if ((node->left = left->right))
	{
		left->right->parent = node;
	}
	left->right = node;

	if ((left->parent = node->parent))
	{
		if (node == node->parent->right)
		{
			node->parent->right = left;
		}
		else
		{
			node->parent->left = left;
		}
	}
	else
	{
		root = left;
	}
	node->parent = left;

	return root;
}

static rb_node_t* rb_insert_rebalance(rb_node_t *node, rb_node_t *root)
{
	rb_node_t *parent, *gparent, *uncle, *tmp;

	while ((parent = node->parent) && parent->color == RED)
	{
		gparent = parent->parent;

		if (parent == gparent->left)
		{
			uncle = gparent->right;
			if (uncle && uncle->color == RED)
			{
				uncle->color = BLACK;
				parent->color = BLACK;
				gparent->color = RED;
				node = gparent;
			}
			else
			{
				if (parent->right == node)
				{
					root = rb_rotate_left(parent, root);
					tmp = parent;
					parent = node;
					node = tmp;
				}

				parent->color = BLACK;
				gparent->color = RED;
				root = rb_rotate_right(gparent, root);
			}
		} 
		else 
		{
			uncle = gparent->left;
			if (uncle && uncle->color == RED)
			{
				uncle->color = BLACK;
				parent->color = BLACK;
				gparent->color = RED;
				node = gparent;
			}
			else
			{
				if (parent->left == node)
				{
					root = rb_rotate_right(parent, root);
					tmp = parent;
					parent = node;
					node = tmp;
				}

				parent->color = BLACK;
				gparent->color = RED;
				root = rb_rotate_left(gparent, root);
			}
		}
	}

	root->color = BLACK;

	return root;
}

static rb_node_t* rb_erase_rebalance(rb_node_t *node, rb_node_t *parent, rb_node_t *root)
{
	rb_node_t *other, *o_left, *o_right;

	while ((!node || node->color == BLACK) && node != root)
	{
		if (parent->left == node)
		{
			other = parent->right;
			if (other->color == RED)
			{
				other->color = BLACK;
				parent->color = RED;
				root = rb_rotate_left(parent, root);
				other = parent->right;
			}
			if ((!other->left || other->left->color == BLACK) &&
				(!other->right || other->right->color == BLACK))
			{
				other->color = RED;
				node = parent;
				parent = node->parent;
			}
			else
			{
				if (!other->right || other->right->color == BLACK)
				{
					if ((o_left = other->left))
					{
						o_left->color = BLACK;
					}
					other->color = RED;
					root = rb_rotate_right(other, root);
					other = parent->right;
				}
				other->color = parent->color;
				parent->color = BLACK;
				if (other->right)
				{
					other->right->color = BLACK;
				}
				root = rb_rotate_left(parent, root);
				node = root;
				break;
			}
		}
		else
		{
			other = parent->left;
			if (other->color == RED)
			{
				other->color = BLACK;
				parent->color = RED;
				root = rb_rotate_right(parent, root);
				other = parent->left;
			}
			if ((!other->left || other->left->color == BLACK) &&
				(!other->right || other->right->color == BLACK))
			{
				other->color = RED;
				node = parent;
				parent = node->parent;
			}
			else
			{
				if (!other->left || other->left->color == BLACK)
				{
					if ((o_right = other->right))
					{
						o_right->color = BLACK;
					}
					other->color = RED;
					root = rb_rotate_left(other, root);
					other = parent->left;
				}
				other->color = parent->color;
				parent->color = BLACK;
				if (other->left)
				{
					other->left->color = BLACK;
				}
				root = rb_rotate_right(parent, root);
				node = root;
				break;
			}
		}
	}

	if (node)
	{
		node->color = BLACK;
	} 

	return root;
}

static rb_node_t* rb_search_auxiliary(key_t key, rb_node_t* root, rb_node_t** save)
{
	rb_node_t *node = root, *parent = NULL;
	int ret;

	while (node)
	{
		parent = node;
		ret = node->key - key;
		if (0 < ret)
		{
			node = node->left;
		}
		else if (0 > ret)
		{
			node = node->right;
		}
		else
		{
			return node;
		}
	}

	if (save)
	{
		*save = parent;
	}

	return NULL;
}

rb_node_t* rb_insert(key_t key, data_t data, rb_node_t* root)
{
	rb_node_t *parent = NULL, *node;

	parent = NULL;
	if ((node = rb_search_auxiliary(key, root, &parent)))
	{
		return root;
	}

	node = rb_new_node(key, data);
	node->parent = parent; 
	node->left = node->right = NULL;
	node->color = RED;

	if (parent)
	{
		if (parent->key > key)
		{
			parent->left = node;
		}
		else
		{
			parent->right = node;
		}
	}
	else
	{
		root = node;
	}

	return rb_insert_rebalance(node, root);
}

rb_node_t* rb_search(key_t key, rb_node_t* root)
{
	return rb_search_auxiliary(key, root, NULL);
}

rb_node_t* rb_erase(key_t key, rb_node_t *root)
{
	rb_node_t *child, *parent, *old, *left, *node;
	color_t color;

	if (!(node = rb_search_auxiliary(key, root, NULL)))
	{
		printf("key %d is not exist!\n");
		return root;
	}

	old = node;

	if (node->left && node->right)
	{
		node = node->right;
		while ((left = node->left) != NULL)
		{
			node = left;
		}
		child = node->right;
		parent = node->parent;
		color = node->color;

		if (child)
		{
			child->parent = parent;
		}
		if (parent)
		{
			if (parent->left == node)
			{
				parent->left = child;
			}
			else
			{
				parent->right = child;
			}
		}
		else
		{
			root = child;
		}

		if (node->parent == old)
		{
			parent = node;
		}

		node->parent = old->parent;
		node->color = old->color;
		node->right = old->right;
		node->left = old->left;

		if (old->parent)
		{
			if (old->parent->left == old)
			{
				old->parent->left = node;
			}
			else
			{
				old->parent->right = node;
			}
		} 
		else
		{
			root = node;
		}

		old->left->parent = node;
		if (old->right)
		{
			old->right->parent = node;
		}
	}
	else
	{
		if (!node->left)
		{
			child = node->right;
		}
		else if (!node->right)
		{
			child = node->left;
		}
		parent = node->parent;
		color = node->color;

		if (child)
		{
			child->parent = parent;
		}
		if (parent)
		{
			if (parent->left == node)
			{
				parent->left = child;
			}
			else
			{
				parent->right = child;
			}
		}
		else
		{
			root = child;
		}
	}

	free(old);

	if (color == BLACK)
	{
		root = rb_erase_rebalance(child, parent, root);
	}
	system("pause");
	return root;
}

代码下载及其运行

代码下载地址：http://download.csdn.net/detail/yincheng01/6858815

解压密码：c.itcast.cn

下载代码并解压后，用VC2013打开interview.sln，并设置对应的启动项目后，点击运行即可，具体步骤如下：

1）设置启动项目：右键点击解决方案，在弹出菜单中选择“设置启动项目”

2）在下拉框中选择相应项目，项目名和博客编号一致

3）点击“本地Windows调试器”运行

程序运行结果