Create #316 Remove Duplicate Letters.java

Author: zhmuch

#316 Remove Duplicate Letters.java

@@ -0,0 +1,19 @@
+//  Other`s
+
+public class Solution {
+    public String removeDuplicateLetters(String s) {
+        int[] count = new int[26];
+        int pos = 0;
+
+        for(int i = 0; i < s.length(); i++)
+            count[s.charAt(i) - 'a']++;
+
+        for(int i = 0; i < s.length(); i++) {
+            if(s.charAt(i) < s.charAt(pos))
+                pos = i;
+            if(--count[s.charAt(i) - 'a'] == 0)
+                break;
+        }
+        return s.length() == 0? "" : s.charAt(pos) + removeDuplicateLetters(s.substring(pos+1).replaceAll(""+ s.charAt(pos), ""));
+    }
+}