Predict the Most Frequent Next Word in Constant Time

Question

The candidate is asked to implement a work predictor that processes training data to predict the most frequent next word based on given input.

Codemia · Accepted Answer

To predict the most frequent next word, I will use a dictionary (hash map) to store the frequency of each word following a given word. This allows for efficient lookups and updates. The training data will be processed to populate this frequency map.

1. **Process the training data:** Iterate through each sentence, splitting it into words. For each word, update the frequency of the subsequent word in the dictionary.
2. **Prediction function:** When predicting the next word, simply retrieve the word with the highest frequency from the dictionary for the given input word.

The time complexity for processing the training data is O(n), where n is the total number of words. The space complexity is O(m), where m is the number of unique words. The prediction function operates in O(1) time for retrieval, assuming we maintain a sorted list of frequencies.

```python
class WordPredictor:
    def __init__(self):
        self.word_freq = {}

def process_training_data(self, sentences):
        for sentence in sentences:
            words = sentence.split()
            for i in range(len(words) - 1):
                if words[i] not in self.word_freq:
                    self.word_freq[words[i]] = {}
                if words[i + 1] not in self.word_freq[words[i]]:
                    self.word_freq[words[i]][words[i + 1]] = 0
                self.word_freq[words[i]][words[i + 1]] += 1

def predict_next_word(self, word):
        if word in self.word_freq:
            return max(self.word_freq[word], key=self.word_freq[word].get)
        return None
```

To improve the model, I could implement a caching mechanism to store frequently requested predictions. Additionally, I could explore using machine learning techniques for more complex predictions, such as neural networks, if the dataset is large enough.

Predict the Most Frequent Next Word in Constant Time

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