Create 3227-vowels-game-in-a-string.java

Author: sanajitjana

Medium/3227-vowels-game-in-a-string.java

@@ -0,0 +1,34 @@
+/**
+ * Problem: 3227. Vowels Game in a String
+ * 
+ * Alice and Bob are playing a game on a string s.  
+ * - Alice removes any non-empty substring containing an odd number of vowels.
+ * - Bob removes any non-empty substring containing an even number of vowels.  
+ * The game starts with Alice and they take turns optimally.  
+ * The player who cannot make a move loses.  
+ * 
+ * Return true if Alice wins the game, false otherwise.
+ * 
+ * Approach:
+ * The key insight is simple:
+ * - If there is at least one vowel in the string, Alice can remove a substring containing exactly one vowel.
+ * - This leaves Bob in a position where the vowel count is now reduced by one.
+ * - Since both play optimally, Alice can always force a win by repeating this process.
+ * 
+ * So, the solution simply checks whether there is at least one vowel in the string.
+ * 
+ * Time Complexity: O(n), where n is the length of the string.
+ * Space Complexity: O(1), constant space used.
+ */
+public class Solution {
+    public boolean doesAliceWin(String s) {
+        for (int i = 0; i < s.length(); i++) {
+            char ch = s.charAt(i);
+            if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' ||
+                ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') {
+                return true;
+            }
+        }
+        return false;
+    }
+}