Intuition

This problem can be solved by splitting the sentence into words, iterating through each word to check if the given searchWord is a prefix, and returning the index of the first occurrence where this is true.

Approach

Splitting the Sentence:

• Use strings.Fields(sentence) to split the input sentence into words.

Iterating Through Words:

• Use strings.HasPrefix(word, searchWord) to check if the searchWord is a prefix of the current word.

Indexing:

• Return the 1-indexed position (i + 1) of the first word where searchWord is a prefix.
• If no such word exists, return -1.

Complexity

• Time Complexity: $O(n \cdot m)$ where:
• n is the number of words in the sentence.
• m is the average length of words in the sentence.
• Space Complexity: $O(n)$ where:
• Splitting the sentence into words requires O(n) additional space.

Code

Go

```go [] import "strings"

func isPrefixOfWord(sentence string, searchWord string) int { words := strings.Fields(sentence) for index, word := range words { if strings.HasPrefix(word, searchWord) { return index + 1 } } return -1 }

## Java

```java []
class Solution {
    public int isPrefixOfWord(String sentence, String searchWord) {
        String[] splitted = sentence.split(" ");
        for (int i = 0; i < splitted.length; i++) {
            if (splitted[i].startsWith(searchWord)) {
                return i+1;
            }
        }
        return -1;
    }
}