我是初学者,如果这个问题听起来很愚蠢/不清楚或非常容易,请耐心等待。
如何将数字列表添加到一起以达到目标数字或尽可能接近?例如,这里是一个数字列表:(2,3,4,7,20,25),目标= 105.结果应为:(25,25,25,25,3,2)。给定数字的顺序很重要;始终从列表中的最大数字开始并按顺序添加它们以接近给定值,因此它将选择要测试的下一个数字。结果也可能是(20,20,20,20,25),在这种情况下不正确,因为它不遵循数字的顺序。该算法只有跳过下一个数字才能跳过,否则无法跳转。
最佳M
答案 0 :(得分:1)
l=(2,3,4,7,20,25)
goal = 105
a=max(l)
b=0
res=[]
while b<=goal-24:
b+=a
t=goal-b
res.append(a)
g=0
for x in l:
g+=x
if g==t:
res.append(x)
res.append(g-x)
break
print (res)
输出:
>>>
[25, 25, 25, 25, 3, 2]
>>>
我发现这个解决方案,然而,真让我烦恼:-)!棘手的部分是while b<=goal-24:
,其他代码是基本的Python。
答案 1 :(得分:0)
这是对的吗?我现在没有时间进行测试。
def solution(numbers, goal):
curr = 0
numbers = sorted(numbers)
while curr < goal:
if not numbers: break
n = numbers.pop()
while n + curr <= goal:
yield n
curr += n
list(solution([2,3,4,7,20,25], 105))
结果:
[25, 25, 25, 25, 4]
答案 2 :(得分:0)
如果速度不是问题,这是最终正确的答案:
import itertools
def change_maker(coins, amount):
for r in range(amount//max(coins), amount//min(coins)+1):
possibilities = (combo for combo in itertools.combinations_with_replacement(coins, r) if sum(combo) == amount)
try:
result = next(possibilities)
except StopIteration:
# no solution with current r
continue
else:
return result
这将始终返回最佳结果,但在某些情况下可以计算ABSURD组合数量。
样本:
>>> coins = (2, 3, 4, 7, 20, 25)
>>> goals = 105
>>> print(change_maker(coins, goal))
[20, 20, 20, 20, 25]
答案 3 :(得分:0)
我会采用动态编程方法:
def fewest_items_closest_sum_with_repetition(items, goal):
"""
Given an array of items
where each item is 0 < item <= goal
and each item can be used 0 to many times
Find the highest achievable sum <= goal
Return any shortest (fewest items) sequence
which adds to that sum.
"""
assert goal >= 0, "Invalid goal"
# remove any duplicate or invalid items
items = set(item for item in items if 0 < item <= goal)
# sort descending (work with largest values first)
items = sorted(items, reverse=True)
# start with the no-item sequence
best = {0: []}
active = {0: []}
# while we have further seeds to work from
while active:
nactive = {}
for item in items:
for total, seq in active.items():
# find next achievable sum
ntotal = total + item
# if it is a valid subgoal and has not already been found
if (ntotal <= goal and ntotal not in best):
# save it
best[ntotal] = nactive[ntotal] = [item] + seq
if ntotal == goal:
# best possible solution has been found!
break
active = nactive
# return the best solution found
return best[max(best)]
然后像
一样运行>>> fewest_items_closest_sum_with_repetition([2,3,4,7,20,25], 105)
[25, 20, 20, 20, 20]
>>> fewest_items_closest_sum_with_repetition((40,79), 80)
[40, 40]