1566. Check If A Word Occurs As A Prefix Of Any Word In A Sentence¶

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1566. Check If a Word Occurs As a Prefix of Any Word in a Sentence

Easy

Given a sentence that consists of some words separated by a single space, and a searchWord, check if searchWord is a prefix of any word in sentence.

Return the index of the word in sentence (1-indexed) where searchWord is a prefix of this word. If searchWord is a prefix of more than one word, return the index of the first word (minimum index). If there is no such word return -1.

A prefix of a string s is any leading contiguous substring of s.

Example 1:

Input: sentence = "i love eating burger", searchWord = "burg"
Output: 4
Explanation: "burg" is prefix of "burger" which is the 4th word in the sentence.

Example 2:

Input: sentence = "this problem is an easy problem", searchWord = "pro"
Output: 2
Explanation: "pro" is prefix of "problem" which is the 2nd and the 6th word in the sentence, but we return 2 as it's the minimal index.

Example 3:

Input: sentence = "i am tired", searchWord = "you"
Output: -1
Explanation: "you" is not a prefix of any word in the sentence.

Constraints:

• 1 <= sentence.length <= 100
• 1 <= searchWord.length <= 10
• sentence consists of lowercase English letters and spaces.
• searchWord consists of lowercase English letters.

Solution¶

class Solution {
    public int isPrefixOfWord(String sentence, String target) {
        int n = sentence.length();
        ArrayList<String> res = new ArrayList<>();
        sentence += " ";
        String current = "";
        for (int i = 0; i < sentence.length(); i++) {
            char curr = sentence.charAt(i);
            if (curr == ' ') {
                res.add(current);
                current = "";
            }
            else current += curr;
        }
        for (int i = 0; i < res.size(); i++) {
            if (res.get(i).startsWith(target)) return i + 1;
        }
        return -1;
    }
}

Complexity Analysis¶

• Time Complexity: O(?)
• Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here