Initial data commit

Task/Damm-algorithm/D/damm-algorithm.d

@@ -0,0 +1,36 @@
+import std.stdio;
+
+auto 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],
+];
+
+bool damm(string s) {
+    int interim = 0;
+    foreach (c; s) {
+        interim = table[interim][c - '0'];
+    }
+    return interim == 0;
+}
+
+void main() {
+    import std.conv : to;
+    auto numbers = [5724, 5727, 112946, 112949];
+    foreach (number; numbers) {
+        bool isValid = damm(number.to!string());
+        writef("%6d is ", number);
+        if (isValid) {
+            writeln("valid");
+        } else {
+            writeln("invalid");
+        }
+    }
+}