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.
Constraints:
1 <= sentence.length <= 100
1 <= searchWord.length <= 10
sentence consists of lowercase English letters and spaces.
searchWord consists of lowercase English letters.
思路一：分割字符串后遍历
public int isPrefixOfWord(String sentence, String searchWord) {
String[] split = sentence.split("\\s");
for (int i = 0; i < split.length; i++) {
if (split[i].startsWith(searchWord)) {
return i + 1;
}
}
return -1;
}
思路二：直接在字符串上进行比对
public int isPrefixOfWord(String sentence, String searchWord) {
int idx = 0;
sentence = " " + sentence;
outer:
for (int i = 0; i < sentence.length(); i++) {
if (sentence.charAt(i) == ' ') {
idx++;
for (int j = 0; j < searchWord.length(); j++) {
if (sentence.charAt(i + j + 1) != searchWord.charAt(j)) {
continue outer;
}
}
return idx;
}
}
return -1;
}