我们可以使用Aho-Corasick算法来匹配多个模式组。在这个应用中,我们需要将每个模式组如图解压缩到类似trie的结构中。然后我们创建一个队列(queue)用于处理每一轮匹配。每个队列元素代表当前匹配到的位置和包含在某个模式组中的模式。 最后,我们使用自动机匹配算法在每个队列元素中使用匹配的模式组。其中还需要使用状态转移函数计算出下一个队列元素。整个匹配过程在每个队列上重复进行直到队列为空为止。下面是代码示例:
class ACNode:
def __init__(self):
self.fail = None
self.paths = {}
self.pattern_ids = []
def build_trie(patterns):
root = ACNode()
for idx, p in enumerate(patterns):
node = root
for c in p:
node.paths[c] = node.paths.get(c, ACNode())
node = node.paths[c]
node.pattern_ids.append(idx)
return root
def match(text, patterns):
trie_root = build_trie(patterns)
text_len = len(text)
queue = [(trie_root, -1, set())]
for i in range(text_len):
new_queue = []
for node, idx, matched_pattern_idx in queue:
for c, child in node.paths.items():
if c == text[i]:
new_idx = idx + 1
else:
next_node = node.fail
while next_node and c not in next_node.paths:
next_node = next_node.fail
if next_node:
new_idx = 0
child = next_node.paths[c]
else:
new_idx = -1
child = trie_root
new_matched_pattern_idx = matched_pattern_idx.union(child.pattern_ids)
if child.pattern_ids:
new_queue.append((child, new_idx, new_matched_pattern_idx))
if child.fail:
fail_node = child.fail
while fail_node:
new_matched_pattern_idx = matched_pattern_idx.union(fail_node.pattern_ids)
new_queue.append((fail_node, new_idx, new_matched_pattern_idx))
fail_node = fail_node.fail
queue = new_queue
if not queue:
break
return [matched_pattern_idx for node, idx, matched_pattern_idx in queue]