大厂笔试真题：纸币问题编程

序：假设1元、2元、5元、10元、50元、100元的纸币，长数不限制，现在要用来支付M元，至少要多少张纸币？
(Suppose there is no limit to the number of notes of 1 yuan, 2 yuan, 5 yuan, 10 yuan, 50 yuan and 100 yuan. Now, how many notes do you need to pay for M yuan?)