algorithm-in-python/dynamicProgramming/splitStripe.py
2020-04-15 12:28:20 +08:00

52 lines
1.6 KiB
Python

''' mbinary
#########################################################################
# File : splitStripe.py
# Author: mbinary
# Mail: zhuheqin1@gmail.com
# Blog: https://mbinary.xyz
# Github: https://github.com/mbinary
# Created Time: 2018-08-24 17:07
# Description:
#########################################################################
'''
'''
There is stripe which length is n,
priceMap contains a map for different length of stripe and its price
then find the maximum price to split the stripe in different shorter stripes
( including the original length if possible)
'''
def count(n, prices):
def best(cur):
# note that copying the list or create a new list in the following new_stripes codes
if cur in values:
return values[cur], stripes[cur]
maxPrice = 0
new_stripes = []
for i, j in prices.items():
if i <= cur:
p, tmp = best(cur-i)
if maxPrice < p+j:
# if the list is not copyed, create a new list, don't use append
new_stripes = tmp+[i]
maxPrice = p+j
values[cur] = maxPrice
stripes[cur] = new_stripes
return maxPrice, new_stripes
values = {0: 0}
stripes = {0: []}
return best(n)
if __name__ == '__main__':
li = [(1, 1), (2, 5), (3, 8), (4, 9), (5, 10),
(6, 17), (7, 17), (8, 20), (9, 24), (10, 30)]
prices = {i: j for i, j in li}
n = 40
d = {i: count(i, prices) for i in range(n+1)}
for i in range(n+1):
print(i, d[i])