Today is an example of The non-Designer's Design Book on Page 42 and Check If a Word Occurs As a Prefix of Any Word in a Sentence on leetcode with cpp.

The non-Designer's Design Book

my answer:

• [T] reduce the distance between serial numbers and items
• [T] change 6 in title to word six so it doesn't confuse the reader
• [T] increase the size of the font of the title
• increase size of the image so it aligns with text both on top and bottom

I got 3/3 of the correct rate, and I think the one answer doesn't give is also a useful difference!

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

Description

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

Solution

simple question, but remember that string.length() returns size_t which is a unsigned number, which leads to first Runtime Errro :(

class Solution {
public:
  bool isPrefixOfIndex(const int offset, const string& prefix, const string& str) {
    for (int i = 0; i < prefix.length(); ++i) {
      if (prefix[i] != str[offset + i]) {
        return false;
      }
    }
    return true;
  }
  int isPrefixOfWord(string sentence, string searchWord) {
    int count = 0;
    for (int i = 0; i <= int(sentence.length()) - int(searchWord.length()); ++i) {
      if (sentence[i] == ' ') {
        count += 1;
      } else if (!i || sentence[i - 1] == ' ') {
        if (isPrefixOfIndex(i, searchWord, sentence)) {
          return count + 1;
        }
      }
    }
    return -1;
  }
};