Initial data commit

Task/Damm-algorithm/Java/damm-algorithm.java

@@ -0,0 +1,32 @@
+public class DammAlgorithm {
+    private static final int[][] table = {
+        {0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
+        {7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
+        {4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
+        {1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
+        {6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
+        {3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
+        {5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
+        {8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
+        {9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
+        {2, 5, 8, 1, 4, 3, 6, 7, 9, 0},
+    };
+
+    private static boolean damm(String s) {
+        int interim = 0;
+        for (char c : s.toCharArray()) interim = table[interim][c - '0'];
+        return interim == 0;
+    }
+
+    public static void main(String[] args) {
+        int[] numbers = {5724, 5727, 112946, 112949};
+        for (Integer number : numbers) {
+            boolean isValid = damm(number.toString());
+            if (isValid) {
+                System.out.printf("%6d is valid\n", number);
+            } else {
+                System.out.printf("%6d is invalid\n", number);
+            }
+        }
+    }
+}