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max_heap.c
148 lines (128 loc) · 2.18 KB
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max_heap.c
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#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#define PARENT(i) ((i)>>1)
#define LEFT(i) ((i)<<1)
#define RIGHT(i) (((i)<<1)+1)
#define HEAP_SIZE 10
inline void exchange(int *a, int *b)
{
int c;
c = *a;
*a = *b;
*b = c;
}
void print_heap(int *a)
{
int i;
for(i=1;i<= a[0];i++){
printf("a[%d]=%d\t",i,a[i]);
if(!(i%10))
puts("\n");
}
}
//a[0] store heap_size
#ifndef ITERATION
void max_heapify(int *a, int i)
{
int left = LEFT(i);
int right = RIGHT(i);
int large = i;
if (left <= a[0] && a[left] > a[i])
large = left;
if (right <= a[0] && a[right] > a[large])
large = right;
if (large != i){
exchange(&a[i],&a[large]);
max_heapify(a, large);
}
}
#else
void max_heapify(int *a, int i)
{
int left,right,large=i;
while (i<=a[0]){
left = LEFT(i);
right = RIGHT(i);
if (left <= a[0] && a[left] > a[i])
large = left;
if (right <= a[0] && a[right] > a[large])
large = right;
if (large != i){
exchange(&a[i],&a[large]);
i = large;
} else {
break;
}
}
}
#endif
void build_max_heap(int *a)
{
int i;
a[0]=HEAP_SIZE;
for(i=HEAP_SIZE/2;i>=1;i--)
max_heapify(a,i);
}
void heap_sort(int *a)
{
int i;
build_max_heap(a);
for(i=HEAP_SIZE;i>=2;i--){
exchange(&a[i],&a[1]);
a[0]--;
max_heapify(a,1);
}
}
inline int heap_maximum(int *a)
{
return a[1];
}
int heap_extract_max(int *a)
{
if(a[0] < 1){
printf("heap underflow\n");
exit(-1);
}
int max = a[1];
a[1] = a[a[0]];
a[0] -= a[0];
max_heapify(a,1);
return max;
}
int heap_increase_key(int *a, int i, int key)
{
if (key < a[i]){
printf("new key is smaller than current key\n");
return -1;
}
a[i] = key;
while (i>1 && a[PARENT(i)]<a[i]){
exchange(&a[i], &a[PARENT(i)]);
i = PARENT(i);
}
return 0;
}
int max_heap_insert(int *a, int key)
{
a[0]++;
a[a[0]] = INT_MIN;
heap_increase_key(a,a[0],key);
}
int main(void)
{
int i;
int a[HEAP_SIZE+10];
a[0]=HEAP_SIZE;
srand(time(NULL));
for(i=1;i<=HEAP_SIZE;i++)
a[i] = rand()%100;
print_heap(a);
build_max_heap(a);
//heap_increase_key(a,5,211);
max_heap_insert(a,211);
print_heap(a);
//for(i=1;i<=HEAP_SIZE;i++)
// printf("the largest number in the excess:%d\n",heap_extract_max(a));
return 0;
}