1 files changed, 31 insertions, 0 deletions
diff --git a/challenge-074/shawn-wagner/java/ch2.java b/challenge-074/shawn-wagner/java/ch2.java
new file mode 100644
index 0000000000..65a8a04a67
--- /dev/null
+++ b/challenge-074/shawn-wagner/java/ch2.java
@@ -0,0 +1,31 @@
+// Same algorithm as the perl version, using a LinkedHashMap to
+// preserve order of keys, and streams to avoid most loops.
+
+import java.util.*;
+
+class ch2 {
+    private static void task2(String s) {
+        ArrayList<Character> chars = new ArrayList<Character>();
+        chars.ensureCapacity(s.length());
+        s.chars().forEach(ch -> chars.add((char)ch));
+        Collections.reverse(chars);
+        StringBuilder sb = new StringBuilder();
+        while (chars.size() > 0) {
+            HashMap<Character, Integer> counts =
+                new LinkedHashMap<Character, Integer>();
+            chars.stream().forEach(ch -> counts.put(ch, counts.getOrDefault(ch, 0) + 1));
+            char fnr = counts.entrySet().stream()
+                .filter(entry -> entry.getValue() == 1)
+                .findFirst().map(entry -> entry.getKey()).orElse('#');
+            sb.append(fnr);
+            chars.remove(0);
+        }
+        sb.reverse();
+        System.out.println(sb);
+    }
+
+    public static void main(String[] args) {
+        task2("ababc");
+        task2("xyzzyx");
+    }
+}