91 lines
1.6 KiB
C
91 lines
1.6 KiB
C
#include "codexion.h"
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#include <stdbool.h>
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#include <stdlib.h>
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static void sift_up(t_minheap *heap, int i, int (*cmp)(void *, void *))
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{
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int parent;
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void *temp;
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while (i > 0)
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{
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parent = (i - 1) / 2;
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if (cmp(heap->array[parent], heap->array[i]) > 0)
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{
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temp = heap->array[parent];
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heap->array[parent] = heap->array[i];
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heap->array[i] = temp;
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i = parent;
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}
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else
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break ;
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}
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}
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static void sift_down(t_minheap *heap, int i, int (*cmp)(void *, void *))
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{
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int smallest;
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int left;
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int right;
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void *temp;
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while (true)
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{
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smallest = i;
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left = 2 * i + 1;
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right = 2 * i + 2;
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if (left < heap->length && cmp(heap->array[left],
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heap->array[smallest]) < 0)
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smallest = left;
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if (right < heap->length && cmp(heap->array[right],
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heap->array[smallest]) < 0)
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smallest = right;
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if (smallest == i)
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break ;
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temp = heap->array[smallest];
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heap->array[smallest] = heap->array[i];
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heap->array[i] = temp;
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i = smallest;
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}
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}
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t_minheap *init_heap(int (*cmp)(void *, void *))
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{
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t_minheap *heap;
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heap = malloc(sizeof(t_minheap));
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if (!heap)
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return (NULL);
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heap->length = 0;
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heap->cmp = cmp;
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return (heap);
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}
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void *peek(t_minheap *heap)
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{
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if (!heap || !heap->length)
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return (NULL);
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return (heap->array[0]);
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}
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void enqueue(t_minheap *heap, void *val)
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{
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if (heap->length >= HEAP_SIZE)
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return ;
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heap->array[heap->length] = val;
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heap->length++;
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sift_up(heap, heap->length - 1, heap->cmp);
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}
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void *dequeue(t_minheap *heap)
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{
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void *temp;
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if (!heap || !heap->length)
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return (NULL);
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temp = heap->array[0];
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heap->array[0] = heap->array[heap->length - 1];
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heap->length--;
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sift_down(heap, 0, heap->cmp);
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return (temp);
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}
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