<p>我有一种感觉,我在这里遗漏了一些非常简单的东西,但是,在这个函数中:</p>
<pre><code>def triplets(perimeter):
triplets, n, a, b, c = 0 #number of triplets, a, b, c, sides of a triangle, n is used to calculate a triple
L = primes(int(math.sqrt(perimeter)) #list of primes to divide the perimeter
for item in L: #iterate through the list of primes
if perimeter % item == 0: #check if a prime divides the perimeter
n = perimeter / item
a = n**2 - (n+1)**2 #http://en.wikipedia.org/wiki/Pythagorean_triple
b = 2n*(n+1)
c = n**2 + n**2
if a+b+c == perimeter: #check if it adds up to the perimeter of the triangle
triplets = triplets + 1
return triplets
</code></pre>
<p>我得到了错误:</p>
<pre><code> for item in L:
^
SyntaxError: invalid syntax
</code></pre>
<p>为了完整起见,我的整个程序如下所示:</p>
<pre><code>import math
def primes(n): #get a list of primes below a number
if n==2: return [2]
elif n<2: return []
s=range(3,n+1,2)
mroot = n ** 0.5
half=(n+1)/2-1
i=0
m=3
while m <= mroot:
if s[i]:
j=(m*m-3)/2
s[j]=0
while j<half:
s[j]=0
j+=m
i=i+1
m=2*i+3
return [2]+[x for x in s if x]
def triplets(perimeter):
triplets, n, a, b, c = 0 #number of triplets, a, b, c, sides of a triangle, n is used to calculate a triple
L = primes(int(math.sqrt(perimeter)) #list of primes to divide the perimeter
for item in L: #iterate through the list of primes
if perimeter % item == 0: #check if a prime divides the perimeter
n = perimeter / item
a = n**2 - (n+1)**2 #http://en.wikipedia.org/wiki/Pythagorean_triple
b = 2n*(n+1)
c = n**2 + n**2
if a+b+c == perimeter: #check if it adds up to the perimeter of the triangle
triplets = triplets + 1
return triplets
def solve():
best = 0
perimeter = 0
for i in range(1, 1000):
if triplets(i) > best:
best = triplets(i)
perimeter = i
return perimeter
print solve()
</code></pre>
<p>我正在使用Python2.7.1。我在for循环后面有一个分号,<code>primes(n)</code>函数可以工作,我有一种感觉,这可能是愚蠢的事情,但我不知道是什么导致了这种无效语法。</p>