#include <assert.h>
#include <stdio.h>
#include <string.h>

void printt(int t[], int n) {
    printf("[");
    for (int i = 0; i < n; i++) {
        printf("%d,", t[i]);
    }
    printf("]\n");
}

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

void quicksort(int t[], int n) {
    if (n <= 1) {
        return;
    }
    int a = 0;
    int b = n - 1;
    int p = t[n - 1];
    while (a < b) {
        if (t[a] <= p)
            a++;
        else if (t[b] >= p)
            b--;
        else {
            swap(t, a, b);
        }
    }
    swap(t, b, n - 1);
    quicksort(t, b);
    quicksort(t + b + 1, n - b - 1);
}

const int t[] = {5, 3, 9, 0, 5, 0};
const int sorted[] = {0, 0, 3, 5, 5, 9};
const int n = 6;

int main() {
    int t1[n];
    memcpy(t1, t, n * sizeof(int));
    quicksort(t1, n);
    assert(memcmp(t1, sorted, n * sizeof(int)) == 0);
}