qsort

qsort.java

private void qsort(int[] a, int bl, int br) {
    if (bl >= br) return;
    int m = a[bl], l = bl, r = br;
    while (l < r) {
        while (l < r && a[r] >= m) r--;
        if (l < r) a[l++] = a[r];
        while (l < r && a[l] <= m) l++;
        if (l < r) a[r--] = a[l];
    }
    a[l] = m;
    qsort(a, bl, l - 1);
    qsort(a, l + 1, br);
}

qsort.py

def qsort(a):
    def _qsort(a, bl, br):
        if not a or bl >= br: return
        m = a[bl]; l = bl; r = br
        while l < r:
            while l < r and a[r] > m: r -= 1
            if l < r: a[l] = a[r]; l += 1
            while l < r and a[l] < m: l += 1
            if l < r: a[r] = a[l]; r -= 1
        a[l] = m
        _qsort(a, bl, l - 1)
        _qsort(a, l + 1, br)
    _qsort(a, bl = 0, br = len(a) - 1)