'''完全参考算法导论第三版实现'''

def PARTITION(A,p,r):
    x = A[r]
    i = p - 1
    for j in range(p,r):
        if A[j] <= x:
            i = i + 1
            A[i],A[j] = A[j],A[i]
    A[i+1],A[r] = A[r],A[i+1]
    return i + 1

def QUICKSORT(A,p,r):
    if p < r:
        q = PARTITION(A,p,r)
        QUICKSORT(A,p,q-1)
        QUICKSORT(A,q+1,r)

if __name__ == '__main__':
    A = [1,3,8,9,12,7,11,90,34,87,88,56,72,39]
    QUICKSORT(A,0,len(A)-1)
    print(A)