第6章 堆排序

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


#define MAX_LEN 10



void print(int* pArray, int size, char* c){
    printf("%s",c);
    for(int i = 0; i < size; ++i){
        printf("%d,",pArray[i]);
    }
}

void max_heap(int *pArray, int index, int size){
    int left_index = (index + 1) * 2 - 1;
    int right_index = (index + 1) * 2;
    int large;
    if(left_index < size && pArray[index] < pArray[left_index]){
        large = left_index;
    }
    else{
        large = index;
    }
    if(right_index < size && pArray[large] < pArray[right_index]){
        large = right_index;
    }
    
    if(large != index){
        int tmp = pArray[large];
        pArray[large] = pArray[index];
        pArray[index] = tmp;
        max_heap(pArray, large, size);
    }
}



void build_max_heap(int* pArray, int max){
    for(int i = ceil(max) / 2 - 1; i >= 0 ; --i){
        max_heap(pArray, i, max);
    }
}

void sort_heap(int* pArray, int max){
    int tmp = 0;
    for(; max; --max){
        build_max_heap(pArray, max);
        tmp = pArray[0];
        pArray[0] = pArray[max-1];
        pArray[max-1] = tmp;
    }
}




int main(void){
    int array[MAX_LEN];
    srand(100);
    for(int i = 0; i < MAX_LEN; ++i){
        array[i] = rand() * 100 / RAND_MAX;
    }
    print(array, MAX_LEN, "before sortheap is:\n");
    sort_heap(array, MAX_LEN);
    print(array, MAX_LEN, "\nafter sort_heap is:\n");
　  return 0;
}
        
        

运行结果：

before sortheap is:
1,3,16,50,74,34,75,5,70,17,
after sort_heap is:
1,3,5,16,17,34,50,70,74,75,