Table of Contents
一、中文版
给你一个字符串 sentence 作为句子并指定检索词为 searchWord ，其中句子由若干用 单个空格 分隔的单词组成。
请你检查检索词 searchWord 是否为句子 sentence 中任意单词的前缀。
- 如果
searchWord是某一个单词的前缀，则返回句子sentence中该单词所对应的下标（下标从 1 开始）。 - 如果
searchWord是多个单词的前缀，则返回匹配的第一个单词的下标（最小下标）。 - 如果
searchWord不是任何单词的前缀，则返回 -1 。
字符串 S 的 「前缀」是 S 的任何前导连续子字符串。
示例 1：
输入：sentence = "i love eating burger", searchWord = "burg" 输出：4 解释："burg" 是 "burger" 的前缀，而 "burger" 是句子中第 4 个单词。
示例 2：
输入：sentence = "this problem is an easy problem", searchWord = "pro" 输出：2 解释："pro" 是 "problem" 的前缀，而 "problem" 是句子中第 2 个也是第 6 个单词，但是应该返回最小下标 2 。
示例 3：
输入：sentence = "i am tired", searchWord = "you" 输出：-1 解释："you" 不是句子中任何单词的前缀。
示例 4：
输入：sentence = "i use triple pillow", searchWord = "pill" 输出：4
示例 5：
输入：sentence = "hello from the other side", searchWord = "they" 输出：-1
提示：
1 <= sentence.length <= 1001 <= searchWord.length <= 10sentence由小写英文字母和空格组成。searchWord由小写英文字母组成。- 前缀就是紧密附着于词根的语素，中间不能插入其它成分，并且它的位置是固定的——-位于词根之前。（引用自 前缀_百度百科 ）
二、英文版
Given a sentence that consists of some words separated by a single space, and a searchWord.
You have to check if searchWord is a prefix of any word in sentence.
Return the index of the word in sentence where searchWord is a prefix of this word (1-indexed).
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.
Example 4:
Input: sentence = "i use triple pillow", searchWord = "pill" Output: 4
Example 5:
Input: sentence = "hello from the other side", searchWord = "they" Output: -1
Constraints:
1 <= sentence.length <= 1001 <= searchWord.length <= 10sentenceconsists of lowercase English letters and spaces.searchWordconsists of lowercase English letters.
三、My answer
遍历 sentence 中所有单词，比较前 n （n 是 searchWord 的长度）位 与 searchWord 是否相同：
class Solution:
def isPrefixOfWord(self, sentence: str, searchWord: str) -> int:
s_list = sentence.split()
n = len(searchWord)
for idx, item in enumerate(s_list):
if len(item) < n:
continue
if item[0:n] == searchWord:
return idx+1
return -1四、解题报告
进阶代码，使用 startswith() 函数即可：
class Solution:
def isPrefixOfWord(self, sentence: str, searchWord: str) -> int:
for i,x in enumerate(sentence.split()):
if x.startswith(searchWord):
return i+1
return -1