66 lines
1.4 KiB
C
66 lines
1.4 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <time.h>
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void swap(int* data, size_t i, size_t j) {
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int tmp = data[i];
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data[i] = data[j];
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data[j] = tmp;
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}
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void siftdown(int* data, size_t n, size_t i) {
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while(2*i+1<n) {
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if(2*i+2>=n) {
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if(data[i] < data[2*i+1]) {
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swap(data, i, 2*i+1);
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i = 2*i+1;
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} else {
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break;
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}
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} else {
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if(data[i] < data[2*i+1] && data[2*i+1] > data[2*i+2]) {
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swap(data, i, 2*i+1);
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i = 2*i+1;
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} else if(data[i] < data[2*i+2]) {
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swap(data, i, 2*i+2);
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i = 2*i+2;
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} else {
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break;
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}
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}
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}
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}
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void heapcreate(int* data, size_t n) {
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for(int i = (n-2)/2; i >= 0; i--) {
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siftdown(data, n, i);
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}
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}
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void heapsort(int* data, size_t n) {
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heapcreate(data, n);
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for(size_t i = n-1; i > 0; i--) {
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swap(data, 0, i);
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siftdown(data, i, 0);
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}
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}
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int main( int argc, char *argv[] ) {
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int n = 1000;
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if(argc > 1) n = atoi(argv[1]);
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srand(time(NULL));
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int* data = malloc(sizeof(int)*n);
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for(size_t i = 0; i < n; i++) {
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data[i] = rand();
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}
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heapsort(data,n);
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int prev = data[0];
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for(size_t i = 1; i < n; i++) {
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assert(prev <= data[i]);
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prev = data[i];
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}
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return 0;
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}
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