add priority queue
This commit is contained in:
yihaoDeng
parent
4a883c23c5
commit
ad61d062ff
|
|
@ -0,0 +1,65 @@
|
|||
/*
|
||||
* Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
|
||||
*
|
||||
* This program is free software: you can use, redistribute, and/or modify
|
||||
* it under the terms of the GNU Affero General Public License, version 3
|
||||
* or later ("AGPL"), as published by the Free Software Foundation.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful, but WITHOUT
|
||||
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||||
* FITNESS FOR A PARTICULAR PURPOSE.
|
||||
*
|
||||
* You should have received a copy of the GNU Affero General Public License
|
||||
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
#ifndef TDENGINE_HEAP_H
|
||||
#define TDENGINE_HEAP_H
|
||||
|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
||||
|
||||
#include "os.h"
|
||||
|
||||
struct HeapNode;
|
||||
|
||||
/* Return non-zero if a < b. */
|
||||
typedef int (*HeapCompareFn)(const struct HeapNode* a, const struct HeapNode* b);
|
||||
|
||||
typedef struct HeapNode {
|
||||
struct HeapNode* left;
|
||||
struct HeapNode* right;
|
||||
struct HeapNode* parent;
|
||||
} HeapNode;
|
||||
|
||||
/* A binary min heap. The usual properties hold: the root is the lowest
|
||||
* element in the set, the height of the tree is at most log2(nodes) and
|
||||
* it's always a complete binary tree.
|
||||
*
|
||||
*/
|
||||
typedef struct {
|
||||
HeapNode* min;
|
||||
size_t nelts;
|
||||
HeapCompareFn compFn;
|
||||
} Heap;
|
||||
|
||||
|
||||
Heap* heapCreate(HeapCompareFn fn);
|
||||
|
||||
void heapDestroy(Heap *heap);
|
||||
|
||||
HeapNode* heapMin(const Heap* heap);
|
||||
|
||||
void heapInsert(Heap* heap, HeapNode* node);
|
||||
|
||||
void heapRemove(Heap* heap, struct HeapNode* node);
|
||||
|
||||
void heapDequeue(Heap* heap);
|
||||
|
||||
size_t heapSize(Heap *heap);
|
||||
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif // TDENGINE_HASH_H
|
||||
|
|
@ -0,0 +1,206 @@
|
|||
/*
|
||||
* Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
|
||||
*
|
||||
* This program is free software: you can use, redistribute, and/or modify
|
||||
* it under the terms of the GNU Affero General Public License, version 3
|
||||
* or later ("AGPL"), as published by the Free Software Foundation.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful, but WITHOUT
|
||||
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||||
* FITNESS FOR A PARTICULAR PURPOSE.
|
||||
*
|
||||
* You should have received a copy of the GNU Affero General Public License
|
||||
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
#include "theap.h"
|
||||
|
||||
size_t heapSize(Heap* heap) {
|
||||
return heap->nelts;
|
||||
}
|
||||
|
||||
Heap* heapCreate(HeapCompareFn fn) {
|
||||
Heap *heap = calloc(1, sizeof(Heap));
|
||||
if (heap == NULL) { return NULL; }
|
||||
|
||||
heap->min = NULL;
|
||||
heap->nelts = 0;
|
||||
heap->compFn = fn;
|
||||
return heap;
|
||||
}
|
||||
|
||||
void heapDestroy(Heap *heap) {
|
||||
free(heap);
|
||||
}
|
||||
|
||||
HeapNode* heapMin(const Heap* heap) {
|
||||
return heap->min;
|
||||
}
|
||||
|
||||
/* Swap parent with child. Child moves closer to the root, parent moves away. */
|
||||
static void heapNodeSwap(Heap* heap, HeapNode* parent, HeapNode* child) {
|
||||
HeapNode* sibling;
|
||||
HeapNode t;
|
||||
|
||||
t = *parent;
|
||||
*parent = *child;
|
||||
*child = t;
|
||||
|
||||
parent->parent = child;
|
||||
if (child->left == child) {
|
||||
child->left = parent;
|
||||
sibling = child->right;
|
||||
} else {
|
||||
child->right = parent;
|
||||
sibling = child->left;
|
||||
}
|
||||
if (sibling != NULL)
|
||||
sibling->parent = child;
|
||||
|
||||
if (parent->left != NULL)
|
||||
parent->left->parent = parent;
|
||||
if (parent->right != NULL)
|
||||
parent->right->parent = parent;
|
||||
|
||||
if (child->parent == NULL)
|
||||
heap->min = child;
|
||||
else if (child->parent->left == parent)
|
||||
child->parent->left = child;
|
||||
else
|
||||
child->parent->right = child;
|
||||
}
|
||||
|
||||
void heapInsert(Heap* heap, HeapNode* newnode) {
|
||||
HeapNode** parent;
|
||||
HeapNode** child;
|
||||
unsigned int path;
|
||||
unsigned int n;
|
||||
unsigned int k;
|
||||
|
||||
newnode->left = NULL;
|
||||
newnode->right = NULL;
|
||||
newnode->parent = NULL;
|
||||
|
||||
/* Calculate the path from the root to the insertion point. This is a min
|
||||
* heap so we always insert at the left-most free node of the bottom row.
|
||||
*/
|
||||
path = 0;
|
||||
for (k = 0, n = 1 + heap->nelts; n >= 2; k += 1, n /= 2)
|
||||
path = (path << 1) | (n & 1);
|
||||
|
||||
/* Now traverse the heap using the path we calculated in the previous step. */
|
||||
parent = child = &heap->min;
|
||||
while (k > 0) {
|
||||
parent = child;
|
||||
if (path & 1)
|
||||
child = &(*child)->right;
|
||||
else
|
||||
child = &(*child)->left;
|
||||
path >>= 1;
|
||||
k -= 1;
|
||||
}
|
||||
|
||||
/* Insert the new node. */
|
||||
newnode->parent = *parent;
|
||||
*child = newnode;
|
||||
heap->nelts += 1;
|
||||
|
||||
/* Walk up the tree and check at each node if the heap property holds.
|
||||
* It's a min heap so parent < child must be true.
|
||||
*/
|
||||
while (newnode->parent != NULL && (heap->compFn)(newnode, newnode->parent))
|
||||
heapNodeSwap(heap, newnode->parent, newnode);
|
||||
}
|
||||
|
||||
void heapRemove(Heap* heap, HeapNode* node) {
|
||||
HeapNode* smallest;
|
||||
HeapNode** max;
|
||||
HeapNode* child;
|
||||
unsigned int path;
|
||||
unsigned int k;
|
||||
unsigned int n;
|
||||
|
||||
if (heap->nelts == 0)
|
||||
return;
|
||||
|
||||
/* Calculate the path from the min (the root) to the max, the left-most node
|
||||
* of the bottom row.
|
||||
*/
|
||||
path = 0;
|
||||
for (k = 0, n = heap->nelts; n >= 2; k += 1, n /= 2)
|
||||
path = (path << 1) | (n & 1);
|
||||
|
||||
/* Now traverse the heap using the path we calculated in the previous step. */
|
||||
max = &heap->min;
|
||||
while (k > 0) {
|
||||
if (path & 1)
|
||||
max = &(*max)->right;
|
||||
else
|
||||
max = &(*max)->left;
|
||||
path >>= 1;
|
||||
k -= 1;
|
||||
}
|
||||
|
||||
heap->nelts -= 1;
|
||||
|
||||
/* Unlink the max node. */
|
||||
child = *max;
|
||||
*max = NULL;
|
||||
|
||||
if (child == node) {
|
||||
/* We're removing either the max or the last node in the tree. */
|
||||
if (child == heap->min) {
|
||||
heap->min = NULL;
|
||||
}
|
||||
return;
|
||||
}
|
||||
|
||||
/* Replace the to be deleted node with the max node. */
|
||||
child->left = node->left;
|
||||
child->right = node->right;
|
||||
child->parent = node->parent;
|
||||
|
||||
if (child->left != NULL) {
|
||||
child->left->parent = child;
|
||||
}
|
||||
|
||||
if (child->right != NULL) {
|
||||
child->right->parent = child;
|
||||
}
|
||||
|
||||
if (node->parent == NULL) {
|
||||
heap->min = child;
|
||||
} else if (node->parent->left == node) {
|
||||
node->parent->left = child;
|
||||
} else {
|
||||
node->parent->right = child;
|
||||
}
|
||||
|
||||
/* Walk down the subtree and check at each node if the heap property holds.
|
||||
* It's a min heap so parent < child must be true. If the parent is bigger,
|
||||
* swap it with the smallest child.
|
||||
*/
|
||||
for (;;) {
|
||||
smallest = child;
|
||||
if (child->left != NULL && (heap->compFn)(child->left, smallest))
|
||||
smallest = child->left;
|
||||
if (child->right != NULL && (heap->compFn)(child->right, smallest))
|
||||
smallest = child->right;
|
||||
if (smallest == child)
|
||||
break;
|
||||
heapNodeSwap(heap, child, smallest);
|
||||
}
|
||||
|
||||
/* Walk up the subtree and check that each parent is less than the node
|
||||
* this is required, because `max` node is not guaranteed to be the
|
||||
* actual maximum in tree
|
||||
*/
|
||||
while (child->parent != NULL && (heap->compFn)(child, child->parent))
|
||||
heapNodeSwap(heap, child->parent, child);
|
||||
}
|
||||
|
||||
void heapDequeue(Heap* heap) {
|
||||
heapRemove(heap, heap->min);
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue