Hello, I am a newbie with python, though I am having a lot of fun using
it. Here is one of the excersizes I am trying to complete:
the program is supposed to find the coin combination so that with 10
coins you can reach a certain amoung, taken as a parameter. Here is the
current program:
coins = (100,10,5,1,0.5 )
anslist = []
def bar(fin, hist = {100:0,10:0,5:0 ,1:0,0.5:0}):
s = sum(x*hist[x] for x in hist)
l = sum(hist.values ())
if s < fin and l < 10:
for c in coins:
if (s+c) <= fin:
hist[c] += 1
bar(fin, hist)
hist[c] -= 1
elif l==10 and s==fin and not hist in anslist:
#p1
anslist.append( hist)
bar(50)
print anslist
The problem is that if I run it, anslist prints as [{0.5: 0, 1: 0, 10:
0, 100: 0, 5: 0}], which doesnt even add up to 50. When I check how
many times the program has reached the #p1 by sticking a print there,
it only reaches it once, and it comes out correct. why is it that this
result is replaced by the incorrect final one? 9 2100
smartbei schrieb:
Hello, I am a newbie with python, though I am having a lot of fun using
it. Here is one of the excersizes I am trying to complete:
the program is supposed to find the coin combination so that with 10
coins you can reach a certain amoung, taken as a parameter. Here is the
current program:
coins = (100,10,5,1,0.5 )
anslist = []
def bar(fin, hist = {100:0,10:0,5:0 ,1:0,0.5:0}):
s = sum(x*hist[x] for x in hist)
l = sum(hist.values ())
if s < fin and l < 10:
for c in coins:
if (s+c) <= fin:
hist[c] += 1
bar(fin, hist)
hist[c] -= 1
elif l==10 and s==fin and not hist in anslist:
#p1
anslist.append( hist)
bar(50)
print anslist
The problem is that if I run it, anslist prints as [{0.5: 0, 1: 0, 10:
0, 100: 0, 5: 0}], which doesnt even add up to 50. When I check how
many times the program has reached the #p1 by sticking a print there,
it only reaches it once, and it comes out correct. why is it that this
result is replaced by the incorrect final one?
hist is stored in anslist as a pointer only, therfore the hist[c] -= 1
operates on the same dict as is stored in the anslist. Try the following
in the python interpreter:
a = { 'key' : 1 }
l = [a]
l[0]['key'] -= 1
a
instead use:
anslist.append( dict(hist.items ))
which will copy the dict.
Felix Benner wrote:
smartbei schrieb:
Hello, I am a newbie with python, though I am having a lot of fun using
it. Here is one of the excersizes I am trying to complete:
the program is supposed to find the coin combination so that with 10
coins you can reach a certain amoung, taken as a parameter. Here is the
current program:
coins = (100,10,5,1,0.5 )
anslist = []
def bar(fin, hist = {100:0,10:0,5:0 ,1:0,0.5:0}):
s = sum(x*hist[x] for x in hist)
l = sum(hist.values ())
if s < fin and l < 10:
for c in coins:
if (s+c) <= fin:
hist[c] += 1
bar(fin, hist)
hist[c] -= 1
elif l==10 and s==fin and not hist in anslist:
#p1
anslist.append( hist)
bar(50)
print anslist
The problem is that if I run it, anslist prints as [{0.5: 0, 1: 0, 10:
0, 100: 0, 5: 0}], which doesnt even add up to 50. When I check how
many times the program has reached the #p1 by sticking a print there,
it only reaches it once, and it comes out correct. why is it that this
result is replaced by the incorrect final one?
hist is stored in anslist as a pointer only, therfore the hist[c] -= 1
operates on the same dict as is stored in the anslist. Try the following
in the python interpreter:
a = { 'key' : 1 }
l = [a]
l[0]['key'] -= 1
a
instead use:
anslist.append( dict(hist.items ))
which will copy the dict.
Thanks!
BTW - its hist.items(), after that it worked.
smartbei wrote:
Felix Benner wrote:
>smartbei schrieb:
>>Hello, I am a newbie with python, though I am having a lot of fun using it. Here is one of the excersizes I am trying to complete: the program is supposed to find the coin combination so that with 10 coins you can reach a certain amoung, taken as a parameter. Here is the current program:
coins = (100,10,5,1,0.5 ) anslist = [] def bar(fin, hist = {100:0,10:0,5:0 ,1:0,0.5:0}): s = sum(x*hist[x] for x in hist) l = sum(hist.values ()) if s < fin and l < 10: for c in coins: if (s+c) <= fin: hist[c] += 1 bar(fin, hist) hist[c] -= 1 elif l==10 and s==fin and not hist in anslist: #p1 anslist.append( hist)
bar(50) print anslist
The problem is that if I run it, anslist prints as [{0.5: 0, 1: 0, 10: 0, 100: 0, 5: 0}], which doesnt even add up to 50. When I check how many times the program has reached the #p1 by sticking a print there, it only reaches it once, and it comes out correct. why is it that this result is replaced by the incorrect final one?
hist is stored in anslist as a pointer only, therfore the hist[c] -= 1 operates on the same dict as is stored in the anslist. Try the following in the python interpreter:
a = { 'key' : 1 } l = [a] l[0]['key'] -= 1 a
instead use:
anslist.append (dict(hist.item s))
which will copy the dict.
Thanks!
BTW - its hist.items(), after that it worked.
An alternative.
cointypes = (100, 10, 5, 1, 0.5)
needed = {}
def coins(fin):
cur = fin
for c in cointypes:
v = int(cur / c)
if v 0:
needed[c] = v
cur -= v * c
if __name__ == '__main__':
coins(51)
print needed
coins(127)
print needed
Better alternative.
cointype = (100, 10, 5, 1, 0.5)
def coins(fin):
needed = {}
for c in cointypes:
v, r = divmod(fin, c)
if v 0:
needed[c] = v
fin = r
return needed
if __name__ == '__main__':
print coins(51)
print coins(127)
print coins[12.5)
"Paul Watson дµÀ£º
<snip>
Interesting impl in Python! I am wondering what if the requirement is
to find the minimum number of coins which added to the "fin" sum... go****@yahoo.co m wrote:
> Interesting impl in Python! I am wondering what if the requirement is to find the minimum number of coins which added to the "fin" sum...
Given the set of coins in the original problem (100, 10, 5, 1, 0.5), the
solution it provides will always be optimal. Even if we change this to
American coinage (50, 25, 10, 5, 1), I believe it is still optimal.
It is certainly possible to construct a set of denominations for which the
algorithm occasionally chooses badly. For example, if you give it the set
(40,35,10) and ask it to make change for 70, it will be suboptimal.
--
Tim Roberts, ti**@probo.com
Providenza & Boekelheide, Inc.
Tim Roberts wrote:
go****@yahoo.co m wrote:
>Interesting impl in Python! I am wondering what if the requirement is to find the minimum number of coins which added to the "fin" sum...
Given the set of coins in the original problem (100, 10, 5, 1, 0.5), the
solution it provides will always be optimal. Even if we change this to
American coinage (50, 25, 10, 5, 1), I believe it is still optimal.
It is certainly possible to construct a set of denominations for which the
algorithm occasionally chooses badly. For example, if you give it the set
(40,35,10) and ask it to make change for 70, it will be suboptimal.
Tim,
Unless I am missing the point, the minimum number of coins from the set
available will be chosen. Surely this homework is past due by now.
$ cat coins.py
#!/usr/bin/env python
import sys
cointypes = (100, 10, 5, 1, 0.5)
def coins(fin, cointypes):
needed = {}
for c in cointypes:
v, r = divmod(fin, c)
if v 0:
needed[c] = int(v)
fin = r
return needed
def doit(fin, cointypes = cointypes):
h = coins(fin, cointypes)
print '%.1f requires %d coins in hash ' % (fin, sum(h.values()) ), h
if __name__ == '__main__':
doit(51)
doit(127)
doit(12.5)
doit(70, (40,35,10))
sys.exit(0)
$ ./coins.py
51.0 requires 6 coins in hash {1: 1, 10: 5}
127.0 requires 6 coins in hash {1: 2, 10: 2, 100: 1, 5: 1}
12.5 requires 4 coins in hash {0.5: 1, 1: 2, 10: 1}
70.0 requires 4 coins in hash {40: 1, 10: 3}
Paul Watson wrote:
It is certainly possible to construct a set of denominations for which the
algorithm occasionally chooses badly. For example, if you give it the set
(40,35,10) and ask it to make change for 70, it will be suboptimal.
Unless I am missing the point, the minimum number of coins from the set
available will be chosen. Surely this homework is past due by now.
[...]
doit(70, (40,35,10))
70.0 requires 4 coins in hash {40: 1, 10: 3}
The point was that "minimum number of coins" in this case is actually
two, but the provided algorithm yields four.
-tom!
--
"Paul Watson дµÀ£º
"
Tim Roberts wrote:
go****@yahoo.co m wrote:
Interesting impl in Python! I am wondering what if the requirement is
to find the minimum number of coins which added to the "fin" sum...
Given the set of coins in the original problem (100, 10, 5, 1, 0.5), the
solution it provides will always be optimal. Even if we change this to
American coinage (50, 25, 10, 5, 1), I believe it is still optimal.
It is certainly possible to construct a set of denominations for which the
algorithm occasionally chooses badly. For example, if you give it the set
(40,35,10) and ask it to make change for 70, it will be suboptimal.
Tim,
Unless I am missing the point, the minimum number of coins from the set
available will be chosen. Surely this homework is past due by now.
$ cat coins.py
#!/usr/bin/env python
import sys
cointypes = (100, 10, 5, 1, 0.5)
def coins(fin, cointypes):
needed = {}
for c in cointypes:
v, r = divmod(fin, c)
if v 0:
needed[c] = int(v)
fin = r
return needed
def doit(fin, cointypes = cointypes):
h = coins(fin, cointypes)
print '%.1f requires %d coins in hash ' % (fin, sum(h.values()) ), h
if __name__ == '__main__':
doit(51)
doit(127)
doit(12.5)
doit(70, (40,35,10))
sys.exit(0)
$ ./coins.py
51.0 requires 6 coins in hash {1: 1, 10: 5}
127.0 requires 6 coins in hash {1: 2, 10: 2, 100: 1, 5: 1}
12.5 requires 4 coins in hash {0.5: 1, 1: 2, 10: 1}
70.0 requires 4 coins in hash {40: 1, 10: 3}
To be explicit, the min coins question could be resolved with "dynamic
programming". So it is not a pure python question. No, this is not a
homework question. Well, it is somewhat academic: http://www.topcoder.com/tc?module=St...als&d2=dynProg
I wrote the following Python implementation akin to topcoder algorithm:
#!/usr/bin/env python
default_cointyp es = (1, 3, 5)
def mincoins(fin, cointypes = default_cointyp es):
needed = {}
for c in cointypes:
needed[c] = 0
min = {}
for item in range(1, fin+1):
min[item] = 2007 # suppose 2007 is the "infinity"
min[0] = 0
for i in range(1, fin+1):
for c in cointypes:
if (c <= i and min[i-c] + 1 < min[i]):
min[i] = min[i-c] + 1
needed[c] += 1
print fin, "==>", min[fin]
print needed
if __name__ == '__main__':
mincoins(11)
Probably there are things to be improved and there could be the
pythonic way(s): Welcome your comments and ideas!
Happy new year!
Wenjie This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: abcd |
last post by:
kutthaense Secretary Djetvedehald H. Rumsfeld legai predicted eventual
vicmadhlary in Iraq mariyu Afghmadhlaistmadhla, kaani jetvedehly after "a
ljetvedehg, hard slog," mariyu vede legai pressed Pentagjetvedeh
karuvificials madhla reachathe strategy in karkun campaign deshatinst
terrorism.
"mudivae maretu winning or losing karkun global varti jetvedeh terror?" Mr.
Rumsfeld adugued in a recent memormariyuum. vede velli jetvedeh madhla...
|
by: titan0111 |
last post by:
#include<iostream>
#include<iomanip>
#include<cstring>
#include<fstream>
using namespace std;
class snowfall
{
private:
int ft;
|
by: SStory |
last post by:
Hi all,
I really needed to get the icons associated with each file that I want to
show in a listview.
I used the follow modified code sniplets found on the internet.
I have left in commented code for anyone else who may be looking to do the
same.
|
by: abico |
last post by:
Write a program that reads in a sequence of words and prints them in
reverse order.Using STACK.
|
by: c |
last post by:
Hi everybody.
I'm working on converting a program wriiten on perl to C, and facing a
problem with concatenate strings.
Now here is a small program that descripe the problem, if you help me
to solve in this small code, I can solve it on my own program...you
don't want to have head-ache :-)
So, the problem excatly is, I built an array..just like this one.
| |
by: Unebrion |
last post by:
Alright im working on a program that prints out user imput in a frame, along with a barcode.. it is like the front of an envelope. Here is the description for the program.
This part just explains a check digit.. i think this part in my program is alright
These barcodes actually have four parts: a tall line as the first bar, a series of
tall and short lines corresponding to the digits in the ZIP code, a check digit,...
|
by: Jay |
last post by:
I have a multi threaded VB.NET application (4 threads) that I use to send
text messages to many, many employees via system.timer at a 5 second
interval. Basically, I look in a SQL table (queue) to determine who needs
to receive the text message then send the message to the address. Only
problem is, the employee may receive up to 4 of the same messages because
each thread gets the recors then sends the message. I need somehow to
prevent...
|
by: weidongtom |
last post by:
Hi,
I tried to implement the Universal Machine as described in
http://www.boundvariable.org/task.shtml, and I managed to get one
implemented (After looking at what other's have done.) But when I use
to run a UM program, I kept on getting error messages. I have used
someone else's implementation and it runs fine. I have compared my
code with other's and I still can't figure it out what's wrong with
mine. So please help me out, after 3...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
| |
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own....
Now, this would greatly impact the work of software developers. The idea...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
|
by: 6302768590 |
last post by:
Hai team
i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
|
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |