Feature #6: Most Common Token
Description
For this feature of the language compiler, the program statements are given to us as a string. We want to determine the variable or function that is most commonly referred to in a program. In this process, we want to ignore the language keywords. For example, a keyword may be used more frequently than any variable or function. The language keywords are given as an array of strings.
Let’s say you are given the following program as input:
int main() {int value = getValue();int sum = value + getRandom();int subs = value - getRandom();return 0;}
The list of keywords given to you is ["int", "main", "return"]. In this example, your function will return "value". Note that, your functions should ignore syntax, such as parentheses, operators, semicolons, etc.
Solution
We can solve this problem by normalizing the code string and processing it step by step. The complete algorithm is as follows:
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First, we replace all the syntax, including parentheses, operators, semicolons, etc., with spaces. Now, the string only contains alphanumeric tokens.
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Then, we split the code obtained from the previous step into
tokens. -
We iterate through the tokens to count the appearance of each unique token as keys, excluding the keywords.
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We create a HashMap
count, which has tokens as keys and occurrences as values. -
In the end, we check the tokens in
countto find the token with the highest frequency.
def most_common_token(code, keywords):# Replacing the syntax with spacesnormalized_code = ''.join([c if c.isalnum() else ' ' for c in code])tokens = normalized_code.split()count = defaultdict(int)banned_words = set(keywords)# Count occurrence of each token, excluding the keywordsfor token in tokens:if token not in banned_words:count[token] += 1return max(count.items(), key=operator.itemgetter(1))[0]# Driver codecode = """int main() {int value = getValue();int sum = value + getRandom();int subs = value - getRandom();return 0;}"""keywords = ["int", "main", "return"]print(most_common_token(code, keywords))
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