Today I have done leetcode's January LeetCoding Challenge with cpp.

January LeetCoding Challenge 12

Description

Determine if String Halves Are Alike

You are given a string s of even length. Split this string into two halves of equal lengths, and let a be the first half and b be the second half.

Two strings are alike if they have the same number of vowels ('a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U'). Notice that s contains uppercase and lowercase letters.

Return true if a and b are alike. Otherwise, return false.

Example 1:

Input: s = "book"
Output: true
Explanation: a = "bo" and b = "ok". a has 1 vowel and b has 1 vowel. Therefore, they are alike.

Example 2:

Input: s = "textbook"
Output: false
Explanation: a = "text" and b = "book". a has 1 vowel whereas b has 2. Therefore, they are not alike.
Notice that the vowel o is counted twice.

Constraints:

• 2 <= s.length <= 1000
• s.length is even.
• s consists of uppercase and lowercase letters.

Solution

constexpr int vowel(char c) {
  switch(c) {
    case 'a':
    case 'e':
    case 'i':
    case 'o':
    case 'u':
    case 'A':
    case 'E':
    case 'I':
    case 'O':
    case 'U':
      return 1;
  }
  return 0;
}
class Solution {
public:
  bool halvesAreAlike(string s) {
    int front = 0;
    int back = 0;
    int len = s.length();
    for(int i = 0; i < len / 2; ++i) {
      front += vowel(s[i]);
    }
    for(int i = len / 2; i < len; ++i) {
      back += vowel(s[i]);
    }
    return front == back;
  }
};

// Accepted
// 113/113 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 56.35 % of cpp submissions (6.6 MB)