Quicksort

Quicksort(A,p,r) {
    if (p < r) {
       q <- Partition(A,p,r)
       Quicksort(A,p,q)
       Quicksort(A,q+1,r)
    }
}



Partition(A,p,r)
    x <- A[p]
    i <- p-1
    j <- r+1
    while (True) {
        repeat
            j <- j-1
        until (A[j] <= x)
        repeat
            i <- i+1
        until (A[i] >= x)
        if (i A[j]
        else 
            return(j)
    }
}