java - 受限硬币找零问题python java转换

Question

我有一个 python 函数

https://stackoverflow.com/a/44214566/6301603

它计算可能的硬币变化量。每个硬币都有有限的可用性。我试图理解它以将其转换为java但我失败了r=有人可以解释这一行发生了什么吗？

# 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

标签： javapythonlist

Answer 1

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;