C++快速排序

#include<bits/stdc++.h>

using namespace std;

void swap(int a[], int i, int j) {
    int t = a[i];
    a[i] = a[j];
    a[j] = t;
}

int partition(int a[], int p, int r) {
    int i = p;
    int j = r + 1;
    int x = a[p];
    while (1) {
        while (i < r && a[++i] < x);
        while (a[--j] > x);
        if (i >= j) break;
        swap(a, i, j);
    }
    swap(a, p, j);
    return j;
}

void quicksort(int a[], int p, int r) {
    if (p < r) {
        int q = partition(a, p, r);
        quicksort(a, p, q - 1);
        quicksort(a, q + 1, r);
    }
}

int main() {
    int i;
    int a[] = {5, 13, 6, 24, 2, 8, 19, 27, 6, 12, 1, 17};
    int N = 12;
    quicksort(a, 0, N - 1);
    for (i = 0; i < N; i++) printf("%d ", a[i]);
    printf("\n");
    return 0;
}