Add Josephus Problem in Java (Fixes #3345)

archive/j/java/JosephusProblem.java

@@ -0,0 +1,35 @@
+import java.util.*;
+
+public class JosephusProblem {
+
+    private static int josephus(int n, int k) {
+        if (n == 1) return 1;
+        return (josephus(n - 1, k) + k - 1) % n + 1;
+    }
+
+    public static void main(String[] args) {
+        final String usage_msg = "Usage: please input the total number of people and number of people to skip.\n";
+
+        if (args.length != 2) {
+            System.err.print(usage_msg);
+            System.exit(1);
+        }
+
+        int n=0, k=0;
+        try {
+            n = Integer.parseInt(args[0]);
+            k = Integer.parseInt(args[1]);
+        } catch (NumberFormatException e) {
+            System.err.print(usage_msg);
+            System.exit(1);
+        }
+
+        if (n <= 0 || k <= 0) {
+            System.err.print(usage_msg);
+            System.exit(1);
+        }
+
+        int result = josephus(n, k);
+        System.out.println(result);
+    }
+}