我有一个来自的python函数
https://stackoverflow.com/a/44214566/6301603
计算可能发生的硬币找零的数量。每个硬币的可用量有限的地方。我试图理解它以将其转换为java
,但在行r=
中失败了,有人可以解释该行发生了什么吗?
# cs is a list of pairs (c, k) where there's k
# coins of value c.
def limited_coins(cs, n):
r = [1] + [0] * n
for c, k in cs:
# rs[i] will contain the sum r[i] + r[i-c] + r[i-2c] + ...
rs = r[:]
for i in xrange(c, n+1):
rs[i] += rs[i-c]
# This line effectively performs:
# r'[i] = sum(r[i-j*c] for j=0...k)
# but using rs[] so that the computation is O(1)
# and in place.
r[i] += rs[i-c] - (0 if i<c*(k+1) else rs[i-c*(k+1)])
return r[n]
for n in xrange(50):
print n, limited_coins([(1, 3), (2, 2), (5, 3), (10, 2)], n)
谢谢
答案 0 :(得分:0)
将该行替换为
int[] r = new int[n+1];
r[0] = 1;
for (int i = 1; i < r.length; i++)
r[i] = 0;