求解无界背包的朴素Python递归算法--达到精确容量

def unbounded_knapsack(capacity, weights, values):
    n = len(weights)
    if n == 0 or capacity == 0:
        return 0
    
    if weights[n-1] > capacity:
        return unbounded_knapsack(capacity, weights[:n-1], values[:n-1])
    else:
        return max(values[n-1] + unbounded_knapsack(capacity - weights[n-1], weights, values),
                   unbounded_knapsack(capacity, weights[:n-1], values[:n-1]))