g2001_2100.s2063_vowels_of_all_substrings.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g2001_2100.s2063_vowels_of_all_substrings;

// #Medium #String #Dynamic_Programming #Math #Combinatorics
// #2022_05_29_Time_21_ms_(34.49%)_Space_48.9_MB_(68.06%)

public class Solution {
    public long countVowels(String word) {
        long ans = 0;
        for (int i = 0; i < word.length(); i++) {
            if (isVowel(word.charAt(i))) {
                long right = word.length() - (long) i - 1;
                ans += ((long) i + 1) * (right + 1);
            }
        }
        return ans;
    }

    private boolean isVowel(char ch) {
        return ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u';
    }
}