3462. Vowels Game In A String¶

Difficulty: Medium

3462. Vowels Game in a String

Medium

Alice and Bob are playing a game on a string.

You are given a string s, Alice and Bob will take turns playing the following game where Alice starts first:

On Alice's turn, she has to remove any non-empty substring from s that contains an odd number of vowels.
On Bob's turn, he has to remove any non-empty substring from s that contains an even number of vowels.

The first player who cannot make a move on their turn loses the game. We assume that both Alice and Bob play optimally.

Return true if Alice wins the game, and false otherwise.

The English vowels are: a, e, i, o, and u.

Example 1:

Input: s = "leetcoder"

Output: true

Explanation:
Alice can win the game as follows:

Alice plays first, she can delete the underlined substring in s = "leetcoder" which contains 3 vowels. The resulting string is s = "der".
Bob plays second, he can delete the underlined substring in s = "der" which contains 0 vowels. The resulting string is s = "er".
Alice plays third, she can delete the whole string s = "er" which contains 1 vowel.
Bob plays fourth, since the string is empty, there is no valid play for Bob. So Alice wins the game.

Example 2:

Input: s = "bbcd"

Output: false

Explanation:
There is no valid play for Alice in her first turn, so Alice loses the game.

Constraints:

1 <= s.length <= 10⁵
s consists only of lowercase English letters.

Solution¶

class Solution {
    public boolean doesAliceWin(String s) {
        int n = s.length();
        for (int i = 0; i < n; i++) {
            char current = s.charAt(i);
            if (current == 'a' || current == 'e' || current == 'i' || current == 'o' || current == 'u') 
                return true;
        }    
        return false; 
    }
}

Complexity Analysis¶

Time Complexity: O(?)
Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here