擅长:python、mysql、java
<p>只是一个快速的尝试:</p>
<pre><code>def transitive_closure(elements):
elements = set([(x,y) if x < y else (y,x) for x,y in elements])
relations = {}
for x,y in elements:
if x not in relations:
relations[x] = []
relations[x].append(y)
closure = set()
def build_closure(n):
def f(k):
for y in relations.get(k, []):
closure.add((n, y))
f(y)
f(n)
for k in relations.keys():
build_closure(k)
return closure
</code></pre>
<p>执行它,我们会得到</p>
<pre><code>In [3]: transitive_closure([(1,2),(2,3),(3,4)])
Out[3]: set([(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)])
</code></pre>