64 lines
1.1 KiB
Markdown
64 lines
1.1 KiB
Markdown
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---
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title: Heapsort
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TARGET DECK: Obsidian::STEM
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FILE TAGS: algorithm::sorting
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tags:
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- algorithm
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- sorting
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---
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## Overview
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Property | Value
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----------- | --------
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Best Case | -
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Worst Case | -
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Avg. Case | -
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Aux. Memory | -
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Stable | -
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Adaptive | -
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![[heapsort.gif]]
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```c
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inline int left_child(int i) { return (i << 1) + 1; }
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inline int right_child(int i) { return (i << 1) + 2; }
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void max_heapify(int n, int H[static n], int i) {
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while (true) {
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int lc = left_child(i);
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int rc = right_child(i);
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int next = i;
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if (lc < n && H[next] < H[lc]) {
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next = lc;
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}
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if (rc < n && H[next] < H[rc]) {
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next = rc;
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}
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if (next == i) {
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return;
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}
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swap(H, i, next);
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i = next;
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}
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}
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void build_max_heap(int n, int H[static n]) {
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for (int i = n / 2 - 1; i >= 0; --i) {
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max_heapify(n, H, i);
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}
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}
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void heapsort(int n, int H[static n]) {
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build_max_heap(n, H);
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while (n > 1) {
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swap(A, 0, --n);
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max_heapify(n, A, 0);
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}
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}
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```
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## Bibliography
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* Thomas H. Cormen et al., Introduction to Algorithms, Fourth edition (Cambridge, Massachusett: The MIT Press, 2022).
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