Added last byte

Author: FreeTymeKiyan

Other/LastByte.java

@@ -0,0 +1,34 @@
+/**
+ * A type of encoding has only 1 byte encode or 2-byte encode. If the first bit 
+ * is 0, this byte represents 1 character. If the first bit is 1, it represents 
+ * 2 characters. Given a string of bits, find out whether the last char is 1 
+ * byte encoded or 2-byte encoded. 
+ * 
+ * Tags: Recursive
+ */
+class LastByte {
+    public static void main(String[] args) {
+        LastByte l = new LastByte();
+        String s1 = "0xxxxxxx0xxxxxxx0xxxxxxx0xxxxxxx";
+        String s2 = "0xxxxxxx0xxxxxxx1xxxxxxx0xxxxxxx";
+        String s3 = "0xxxxxxx1xxxxxxx1xxxxxxx0xxxxxxx";
+        System.out.println(l.lastByte(s1));
+        System.out.println(l.lastByte(s2));
+        System.out.println(l.lastByte(s3));
+    }
+    
+    /**
+     * Recursive
+     * Check backwards
+     * If s.charAt(-16) is 0, it must be 1
+     * If it is 1, it can be 1 or 0, according to recurse result
+     * Recurse with string without last 8 bit
+     * If returns 1, it means 1xxxxxxx is not connected with string before
+     * If returns 2, it means 1xxxxxxx is part of a 2-byte, return 1
+     */
+    public int lastByte(String s) {
+        if (s == null || s.length() < 16) return 1;
+        if (s.charAt(s.length() - 16) == '0') return 1;
+        return lastByte(s.substring(0, s.length() - 8)) == 1 ? 2 : 1;
+    }
+}