81 lines
1.5 KiB
C
81 lines
1.5 KiB
C
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// Heapsort Algorithm
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// M.Menault 2024
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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void print_array(int* array, int length)
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{
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static int count = 0;
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int i = 0;
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printf("(%3.3d) Array : ",count++);
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for(i=0; i < length; i++)
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{
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printf("%5d ",array[i]);
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}
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printf("\n");
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}
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void sift(int* array, int node, int length)
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{
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int largest_node = node;
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int left_node = 2*node+1;
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int right_node = 2*node+2;
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int temp_value = 0;
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if(left_node < length && array[left_node] > array[largest_node])
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{
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largest_node = left_node;
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}
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if(right_node < length && array[right_node] > array[largest_node])
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{
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largest_node = right_node;
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}
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if(largest_node != node)
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{
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temp_value = array[node];
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array[node] = array[largest_node];
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array[largest_node] = temp_value;
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sift(array,length,largest_node);
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}
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}
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void heapsort(int* array, int length)
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{
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int i = 0;
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int temp_value = 0;
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// Sift the current array (binary tree)
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for(i=(length/2); i >= 0; i--)
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{
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sift(array,i,length);
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}
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// Heapsort !
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for(i=length-1; i > 0; i--)
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{
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temp_value = array[i];
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array[i] = array[0];
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array[0] = temp_value;
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sift(array,0,i);
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}
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}
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void generate_array(int* array, int length)
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{
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int i = 0;
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static int first_call = 1;
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if(first_call)
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{
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first_call = 0;
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srand(time(NULL));
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}
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for(i=0; i < length; i++)
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{
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array[i] = rand() % 20 + 1;
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}
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}
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