leetcode2586: Count the Number of Vowel Strings in Range

[carloscn]

Description

You are given a 0-indexed array of string words and two integers left and right.

A string is called a vowel string if it starts with a vowel character and ends with a vowel character where vowel characters are 'a', 'e', 'i', 'o', and 'u'.

Return the number of vowel strings words[i] where i belongs to the inclusive range [left, right].

Example 1:

Input: words = ["are","amy","u"], left = 0, right = 2
Output: 2
Explanation:

• "are" is a vowel string because it starts with 'a' and ends with 'e'.
• "amy" is not a vowel string because it does not end with a vowel.
• "u" is a vowel string because it starts with 'u' and ends with 'u'.
  The number of vowel strings in the mentioned range is 2.

Example 2:

Input: words = ["hey","aeo","mu","ooo","artro"], left = 1, right = 4
Output: 3
Explanation:

• "aeo" is a vowel string because it starts with 'a' and ends with 'o'.
• "mu" is not a vowel string because it does not start with a vowel.
• "ooo" is a vowel string because it starts with 'o' and ends with 'o'.
• "artro" is a vowel string because it starts with 'a' and ends with 'o'.
  The number of vowel strings in the mentioned range is 3.

Constraints:

1 <= words.length <= 1000
1 <= words[i].length <= 10
words[i] consists of only lowercase English letters.
0 <= left <= right < words.length

[carloscn]

Analysis

static bool is_vowel(char c)
{
    static const char* vowels = "aeiouAEIOU";
    return strchr(vowels, c) != NULL;
}

int32_t vowel_strings(const char* words[], size_t words_size, size_t left, size_t right)
{
    int32_t ret = 0;

    UTILS_CHECK_PTR(words);
    UTILS_CHECK_LEN(words_size);

    if ((right >= words_size) || (left > right)) {
        ret = -1;
        goto finish;
    }

    for (size_t i = left; i <= right; i ++) {
        const char *e = words[i];
        if (NULL == e) {
            continue;
        }

        size_t len = strlen(e);
        if ((len > 0) && is_vowel(e[0]) && is_vowel(e[len - 1])) {
            ret ++;
        }
    }

finish:
    return ret;
}

[carloscn]

Code

https://review.gerrithub.io/c/carloscn/structstudy/+/1172259
eabf390