reverse vowels of a string

fishercoder1534 · fishercoder1534 · commit 9c43313b1080 · 2016-08-17T13:38:39.000-07:00
diff --git a/EASY/src/easy/ReverseVowelsOfAString.java b/EASY/src/easy/ReverseVowelsOfAString.java
@@ -0,0 +1,45 @@
+package easy;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class ReverseVowelsOfAString {
+	public String reverseVowels(String s) {
+		StringBuilder sb = new StringBuilder(s);
+		Set<Character> vowels = new HashSet();
+		vowels.add('a');
+		vowels.add('e');
+		vowels.add('i');
+		vowels.add('o');
+		vowels.add('u');
+		vowels.add('A');
+		vowels.add('E');
+		vowels.add('I');
+		vowels.add('O');
+		vowels.add('U');
+		//use two pointers approach would be the fastest
+		int i = 0, j = s.length()-1;
+		while (i < j){
+			char left = s.charAt(i), right = s.charAt(j);
+			while(i < j && !vowels.contains(left)){
+				i++;
+				left = s.charAt(i);
+			}
+			while(i < j && !vowels.contains(right)){
+				j--;
+				right = s.charAt(j);
+			}
+			char temp = left;
+			sb.setCharAt(i, right);
+			sb.setCharAt(j, temp);
+			i++; j--;
+		}
+		return sb.toString();
+	}
+	
+	public static void main(String...strings){
+		ReverseVowelsOfAString test = new ReverseVowelsOfAString();
+		String s = "leetcode";
+		System.out.println(test.reverseVowels(s));
+	}
+}
