checkio--

checkio进不去，代码vs测试通过应该没问题。暂且保留记录。等待更新

import copy
def checkio(price, denominations):
    l=len(denominations)
    a=denominations
    b=[price]
    p=1
    k=0
    while(max(b)>=min(denominations)):
        for i in b:
            if i in denominations:
                k=1
                break
        if k ==1 :
            break
        p+=1
        c=copy.deepcopy(b)
        b=[]   
        for i in c:
            for j in a:
                b.append(i-j)  
    if k==0:
        return None
    else:
        return p