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spell_checker.py
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spell_checker.py
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import csv
from collections import defaultdict
class TrieNode:
def __init__(self):
self.children = defaultdict(TrieNode)
self.is_end_of_word = False
class Trie:
def __init__(self):
self.root = TrieNode()
def insert(self, word):
node = self.root
for char in word:
node = node.children[char]
node.is_end_of_word = True
def search(self, word):
node = self.root
for char in word:
if char not in node.children:
return False
node = node.children[char]
return node.is_end_of_word
def build_prefix_tree(file_path):
trie = Trie()
with open(file_path, 'r') as file:
reader = csv.DictReader(file)
for row in reader:
word = row['Word'].strip().lower()
trie.insert(word)
return trie
def longest_common_subsequence(word1, word2):
m, n = len(word1), len(word2)
dp = [[0] * (n+1) for _ in range(m+1)]
for i in range(1, m+1):
for j in range(1, n+1):
if word1[i-1] == word2[j-1]:
dp[i][j] = dp[i-1][j-1] + 1
else:
dp[i][j] = max(dp[i-1][j], dp[i][j-1])
return dp[m][n]
def edit_distance(word1, word2):
m, n = len(word1), len(word2)
dp = [[0] * (n+1) for _ in range(m+1)]
for i in range(m+1):
dp[i][0] = i
for j in range(n+1):
dp[0][j] = j
for i in range(1, m+1):
for j in range(1, n+1):
if word1[i-1] == word2[j-1]:
dp[i][j] = dp[i-1][j-1]
else:
dp[i][j] = 1 + min(dp[i-1][j], dp[i][j-1], dp[i-1][j-1])
return dp[m][n]
def spell_checker(input_word, trie):
suggestions = []
def dfs(node, prefix):
if node.is_end_of_word:
lcs_length = longest_common_subsequence(input_word, prefix)
edit_dist = edit_distance(input_word, prefix)
suggestions.append((prefix, lcs_length, edit_dist))
for char, child_node in node.children.items():
dfs(child_node, prefix + char)
dfs(trie.root, "")
suggestions.sort(key=lambda x: (-x[1], x[2]))
return suggestions[0][0]