1704. 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.


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


easy的题目, 一个for循环进行判断即可。


class Solution {
    func halvesAreAlike(_ s: String) -> Bool {
        var vowels:[String] = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"]
        var countA:Int = 0
        var countB:Int = 0
        let arr = Array(s)
        for index in 0...arr.count-1 {
            if vowels.contains(String(arr[index])) {
                if index + 1 <= (arr.count / 2) {
                    countA += 1
                } else {
                    countB += 1
        return countA == countB