1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence


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.


  • 1 <= sentence.length <= 100

  • 1 <= searchWord.length <= 10

  • sentence consists of lowercase English letters and spaces.

  • searchWord consists of lowercase English letters.


func isPrefixOfWord(sentence string, searchWord string) int {
    strs := strings.Fields(sentence)
    for i, s := range strs {
        if check(s, searchWord) { return i + 1 }

    return -1

func check(s string, searchWord string) bool {
    if len(searchWord) > len(s) { return false }

    for i:=0; i<len(searchWord); i++ {
        if s[i] != searchWord[i] {
            return false

    return true

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