google code jam exercise——MilkShakes(3)

還是MilkShakes的問題。今天看了一下Contest Analysis，按照提示總算得到了較好的結果。

在Contest Analysis中，給出了演算法的描述，如下：

1. 初始化flavor choice全為0，檢查customer的滿意情況；

2. 對於不滿意的customer，如果他只喜歡unmalted的，但是所有的已經malted，那麼該customer不可能被滿足，給出IMPOSSIBLE；

3. 對於不滿意的customer，如果他只有一種喜歡的malted，那麼將對應的malted，回到步驟2；

4. 如果沒有不滿意的customer，那麼就是得到瞭解。

在用Python實現的時候，做了一些改進，步驟如下：

1. 初始化flavor choice
遍曆所有customer，如果他只喜歡一種flavor，那麼要滿足他就必須把對應的flavor設為對應的狀態。如果在他之前已經被設定為不同的狀態，那麼他就不可能被滿足，給出IMPOSSIBLE，否則，將沒有被設定的flavor設定為0，繼續下面步驟；

2. 檢查所有customer是否滿意，如果滿意，給出flavor的序列，否則進入迴圈2-3；

3. 更新flavor choice

遍曆不滿意的customer，統計他喜歡的malted的個數，如果為0，即該customer只喜歡unmalted，那麼他不可能被滿足，給出IMPOSSIBLE，如果為1，那麼將對應的flavor設為1，即完成flavor choice的更新

代碼如下：

#!/usr/bin/python
#encoding:UTF-8
#Filename:MilkShakes_Good.py

import sys

def preChoice(customers,flavorNum):
    flag = 1
    flavorSure = []
    flavorChoice = []
for i in range(flavorNum):
        flavorChoice.append(-1)
        flavorSure.append(0)

for i,customer in enumerate(customers):
if customer[0]==1:
if flavorChoice[customer[1]-1]==-1:
                flavorChoice[customer[1]-1] = customer[2]
elif flavorChoice[customer[1]-1]!=customer[2]:
                flag = 0
break
            flavorSure[customer[1]-1] = 1

return [flag,flavorSure,flavorChoice]

def checkSatisfy(customerNum,customers,flavorChoice):
#    for k,sat in enumerate(customerSatisfy):
#        if sat==0:
 customerSatisfy = []
for i in range(customerNum):
        customerSatisfy.append(0)
for k in range(customerNum):
        customer = customers[k]
for i in range(customer[0]):
            j = 2 * i + 1
if flavorChoice[customer[j]-1]==customer[j+1]:
                customerSatisfy[k] = 1
break
return customerSatisfy

def checkAllSatisfy(customerSatisfy):
    flag = 1
for v in customerSatisfy:
if v==0:
            flag = 0
break
return flag


def updateChoice(customers,flavorSure,flavorChoice,customerSatisfy):
    flag = 1
    twoflag = 1 
for k,v in enumerate(customerSatisfy):
if v==0:
            customer = customers[k]
            index = []
for i in range(customer[0]):
                j = 2 * i + 1
if customer[j+1]==1:
                    index.append(j)
if len(index)==0:
                flag = 0
break
elif len(index)==1:
                flavorSure[customer[index[0]]-1] = 1
                flavorChoice[customer[index[0]]-1] = 1
                twoflag = 0
break

if twoflag==1:
print "two more malted in unsatisfied customer\n"
return [flag,flavorSure,flavorChoice]



inname = "input.txt"
outname = "output.txt"
if len(sys.argv)>1:
    inname = sys.argv[1]
    outname = inname.rstrip(".in")
    outname = outname + ".out"
fin = open(inname,"r")
fout = open(outname,"w")

line = fin.readline()

testCaseNum = int(line)

caseNum = 0

for caseNum in range(testCaseNum):
    line = fin.readline()
    flavorNum = int(line)
    line = fin.readline()
    customerNum = int(line)
    customers = []
#    for line in lines:
#    print "Case #%d:" %(caseNum+1)
#    print flavorNum
#    print customerNum
 for i in range(customerNum):
        line = fin.readline()
        line = line.rstrip("\n")
        customer = [int(val) for val in line.split()]
#        print customer
 customers.append(customer)

#    print "\n"

    answer = "Case #%d:" %(caseNum+1)

    tpre = preChoice(customers,flavorNum)

#    print "pre choice:"
#    print tpre

    flag = tpre[0]
if flag == 0:
        answer = answer + " IMPOSSIBLE"
else:
        flavorSure = tpre[1]
        flavorChoice = tpre[2]
for i in range(flavorNum):
if flavorChoice[i]==-1:
                flavorChoice[i] = 0
        customerSatisfy = checkSatisfy(customerNum,customers,flavorChoice)
#        print customerSatisfy
 　　　　allSatisfy = checkAllSatisfy(customerSatisfy) 
#        print allSatisfy

while(allSatisfy==0):
            tpre = updateChoice(customers,flavorSure,flavorChoice,customerSatisfy)
#            print "update:"
#            print tpre
 　　　　　　flag = tpre[0]
if flag==0:
break
else:
                flavorSure = tpre[1]
                flavorChoice = tpre[2]
                customerSatisfy = checkSatisfy(customerNum,customers,flavorChoice)
                allSatisfy = checkAllSatisfy(customerSatisfy) 

if flag==0:
            answer = answer + " IMPOSSIBLE"
else:
for val in flavorChoice:
                answer = answer + " " + str(val)

    answer = answer + "\n"

    fout.write(answer)

fin.close()
fout.close()

這次，small／large case都測試通過。