From 80bc756868d2c415727a4ee6b3fd4e9c344a91c7 Mon Sep 17 00:00:00 2001
From: Orestis <orestis.malaspinas@pm.me>
Date: Mon, 11 Nov 2024 15:44:19 +0100
Subject: [PATCH] added quicksort
---
slides/exemples/quicksort.c | 61 +++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
create mode 100644 slides/exemples/quicksort.c
diff --git a/slides/exemples/quicksort.c b/slides/exemples/quicksort.c
new file mode 100644
index 0000000..0ecc3c4
--- /dev/null
+++ b/slides/exemples/quicksort.c
@@ -0,0 +1,61 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+void print_tab(int size, int tab[size]) {
+ for (int i = 0; i < size; ++i) {
+ printf("%d ", tab[i]);
+ }
+ printf("\n");
+}
+
+void swap(int *lhs, int *rhs) {
+ int tmp = *lhs;
+ *lhs = *rhs;
+ *rhs = tmp;
+}
+
+int partition(int tab[], int ind_min, int ind_max) {
+ // ind_min == 0
+ // ind_max == 6
+ int pivot = tab[ind_max]; // 12
+ int i = ind_min - 1; // 0
+ int j = ind_max; // 6
+ while (i < j) {
+ do {
+ i += 1; // 0, tab[0] == 1 < 12
+ } while (tab[i] < pivot && i < j);
+ do {
+ j -= 1; // j == 5, tab[5] < 12
+ } while (tab[j] > pivot && i < j);
+ if (i < j) {
+ swap(&tab[i], &tab[j]);
+ }
+ }
+ swap(&tab[i], &tab[ind_max]);
+
+ return i;
+}
+
+void quicksort(int tab[], int ind_min, int ind_max) {
+ int size = ind_max - ind_min + 1;
+ if (size > 1) {
+ int ind_pivot = partition(tab, ind_min, ind_max);
+ if (ind_pivot - ind_min > 0) {
+ quicksort(tab, ind_min, ind_pivot - 1);
+ }
+ if (ind_max - ind_pivot > 0) {
+ quicksort(tab, ind_pivot + 1, ind_max);
+ }
+ }
+}
+
+int main(int argc, char *argv[]) {
+ int size = argc - 1;
+ int tab[size];
+ for (int i = 0; i < size; ++i) {
+ tab[i] = atoi(argv[i + 1]);
+ }
+ print_tab(size, tab);
+ quicksort(tab, 0, size - 1);
+ print_tab(size, tab);
+}
--
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