TD1_DEV51_Qualite_Algo/quicksort.c

#include <stdio.h>

// Fonction pour échanger deux entiers
void swap(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

// Partition du tableau
int partition(int arr[], int low, int high) {
    int pivot = arr[high]; // Choisir le dernier élément comme pivot
    int i = low - 1;

    for (int j = low; j < high; j++) {
        if (arr[j] <= pivot) {
            i++;
            swap(&arr[i], &arr[j]);
        }
    }
    swap(&arr[i + 1], &arr[high]);
    return i + 1;
}

// Fonction récursive QuickSort
void quicksort(int arr[], int low, int high) {
    if (low < high) {
        int pi = partition(arr, low, high);
        quicksort(arr, low, pi - 1);
        quicksort(arr, pi + 1, high);
    }
}

// Fonction d'affichage
void printArray(int arr[], int size) {
    for (int i = 0; i < size; i++)
        printf("%d ", arr[i]);
    printf("\n");
}

// Programme principal
int main() {
    int arr[] = {64, 34, 25, 12, 22, 11, 90};
    int n = sizeof(arr) / sizeof(arr[0]);

    printf("Tableau original:\n");
    printArray(arr, n);

    quicksort(arr, 0, n - 1);

    printf("Tableau trie (QuickSort):\n");
    printArray(arr, n);

    return 0;
}