根据 trie search 查找前缀 | | Python

Question

问题： 给定一个 business_names（字符串）列表和一个 searchTerm（字符串）。 返回一个business_names 列表，其中包含searchTerm 作为business_names 中的前缀。

Example 1.
Input:

business_names[] = { "burger king", "McDonald's", "super duper burger's", "subway", "pizza hut"}
searchTerm = "bur"

Ouput:
["burger king", "super duper burger's"]

我已经尝试通过以下方式解决。

但我想实现 trie 方法来解决这个问题。有人请在这里帮忙吗？ https://www.geeksforgeeks.org/trie-insert-and-search/

任何要求解的线性解

def prefix(business_names, searchTerm):
    split = [i.split() for i in business_names]
    ans = []
    for name in split:
        for i in range(len(name)):
            query = ' '.join(name[i:])
            if query.startswith(searchTerm):
                ans.append(name)
                break
    return [' '.join(i) for i in ans]

Answer 1

我不知道trie approach 是什么意思，如果这是你需要的，但我会写得更简单——没有join、range、len

为了确保我也使用lower()

business_names = ["burger king", "McDonald's", "super duper burger's", "subway", "pizza hut"]
searchTerm = "bur"


def prefix(business_names, searchTerm):
    searchTerm = searchTerm.lower()

    results  = []
    for name in business_names:
        for word in name.split(' '):
            word = word.lower()
            if word.startswith(searchTerm):
                results.append(name)
                break

    return results
    
print(prefix(business_names, searchTerm))

---

编辑：

我从链接中获取代码并创建此代码。

但我必须改变两件事。

• 它只适用于字母a-z，所以我必须删除'并转换为lower()

• 它只搜索完整的单词，但在删除 return pCrawl != None and pCrawl.isEndOfWord 中的 and pCrawl.isEndOfWord 之后，它似乎找到了统计为 searchTerm 的单词

但我有一个疑问：也许它比O(n^2) 搜索得更好，但首先它必须构建Trie，而且还需要一些时间。因此，当您总是在相同的文本中搜索并且您只需构建一次 Trie 时，它会很有用。但是您必须为每个企业名称建立单独的Trie - 而且它不必更快。

.

class TrieNode: 
      
    # Trie node class 
    def __init__(self): 
        self.children = [None]*26
  
        # isEndOfWord is True if node represent the end of the word 
        self.isEndOfWord = False
  
class Trie: 
      
    # Trie data structure class 
    def __init__(self): 
        self.root = self.getNode() 
  
    def getNode(self): 
      
        # Returns new trie node (initialized to NULLs) 
        return TrieNode() 
  
    def _charToIndex(self,ch): 
          
        # private helper function 
        # Converts key current character into index 
        # use only 'a' through 'z' and lower case 
          
        return ord(ch)-ord('a') 
  
  
    def insert(self, key): 
          
        # If not present, inserts key into trie 
        # If the key is prefix of trie node,  
        # just marks leaf node 
        pCrawl = self.root 
        length = len(key) 
        for level in range(length): 
            index = self._charToIndex(key[level]) 
  
            # if current character is not present 
            if not pCrawl.children[index]: 
                pCrawl.children[index] = self.getNode() 
            pCrawl = pCrawl.children[index] 
  
        # mark last node as leaf 
        pCrawl.isEndOfWord = True
  
    def search(self, key): 
          
        # Search key in the trie 
        # Returns true if key presents  
        # in trie, else false 
        pCrawl = self.root 
        length = len(key) 
        for level in range(length): 
            index = self._charToIndex(key[level]) 
            if not pCrawl.children[index]: 
                return False
            pCrawl = pCrawl.children[index] 
  
        return pCrawl != None #and pCrawl.isEndOfWord  # <-- check `isEndOfWord` to search full words
  
# driver function 

def prefix(business_names, searchTerm):
  
    searchTerm = searchTerm.lower()

    results  = []
    
    for name in business_names:
    
        # Input keys (use only 'a' through 'z' and lower case) 
        # remove `'`  and convert to list with lower case words
        keys = name.lower().replace("'", "").split(" ")
        #print('keys:', keys)
        
        # Trie object 
        t = Trie() 
  
        # Construct trie 
        for key in keys: 
            #print('key:', key)
            t.insert(key) 

        # Search in trie
        if t.search(searchTerm) is True:
            results.append(name)        
        
    return results
  
if __name__ == '__main__': 

    business_names = ["burger king", "McDonald's", "super duper burger's", "subway", "pizza hut"]
    searchTerm = "bur"
    
    results = prefix(business_names, searchTerm)

    print( results )