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[英]Find the largest palindrome made from the product of two 3-digit numbers using numpy
[英]where am I going going wrong in my calculations to get largest palindrome made from the product of two 3-digit numbers?
我正在做項目Euler問題,以幫助我理解此處有人建議的算法背后的數學。 我不想要代碼,而只是想朝着正確的方向來找出我要去哪里的地方。
def genYieldThreeValues(stop):
j = 999
while stop >99 and j > 99:
multiples = str(stop * j)
front = multiples[:3] # get front three numbers
back = multiples[-3:] # get last three numbers
stop-=1
j-=1
yield [front,back,multiples] # yield a list with first three, last three and all numbers
def highestPalindrome(n):
for x in genYieldThreeValues(n):
if x[1] ==x[0][::-1]: # compare first three and last three digits reversed
return x[2] # if they match return value
print(highestPalindrome(999))
(編輯:新代碼)
def genYieldThreeValues(stop):
while stop >99:
yield stop
def highestPalindrome(n):
highest = 0
for x in range(genYieldThreeValues(n).next(),99,-1):
for i in range(x,99,-1):
product = str(x*i)
if product[::-1] == product and product > highest:
if len(product) > 5:
highest = product
return highest
您正在遞減都stop
和j
在同一個循環,這樣就只生成平方999*999
, 998*998
, 997*997
,等等。沒有進一步研究你的代碼,我想你想要的是離開stop
在不斷genThreeValues
,而是使用具有多個stop
值的那個生成器。
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