inverted index

class InvertedIndex:
    def __init__(self):
        self.index = {}

    def add_document(self, doc_id, content):
        words = content.lower().split()
        for word in words:
            if word not in self.index:
                self.index[word] = set()
            self.index[word].add(doc_id)

    def search(self, query):
        query_words = query.lower().split()
        result = set.intersection(*[self.index.get(word, set()) for word in query_words])
        return list(result)

# Usage
index = InvertedIndex()
index.add_document(1, "Java performance tuning techniques")
index.add_document(2, "Optimizing JVM for high throughput")
index.add_document(3, "Python vs Java: A performance comparison")

print(index.search("java performance"))  # Output: [1, 3]