Day 3 in Dart

diff --git a/03-door-codes/day3.dart b/03-door-codes/day3.dart
new file mode 100644 (file)
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--- /dev/null
+++ b/03-door-codes/day3.dart
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+int o(String char) {
+  return char.codeUnitAt(0) - 'a'.codeUnitAt(0) + 1;
+}
+
+int n(int rune) {
+  return rune - 'a'.codeUnitAt(0) + 1;
+}
+
+
+String c(int num) {
+  return new String.fromCharCode((num - 1) % 26 + 'a'.codeUnitAt(0));
+}
+
+var letters = new RegExp(r'[a-z]');
+
+String code1(String expanded_passphrase) {
+  String passphrase = letters.allMatches(expanded_passphrase).map((Match m) => m[0]).join();
+  String c0 = passphrase[0];
+  String c1 = passphrase[1];
+  passphrase.substring(2).runes.forEach((int rune) {
+    c0 = c(o(c0) + o(c1));
+    c1 = c(o(c1) + n(rune));
+  });
+  return c0 + c1;
+}
+
+String code2(String expanded_passphrase) {
+  String passphrase = letters.allMatches(expanded_passphrase).map((Match m) => m[0]).join();
+  int alpha = 5;
+  int beta = 11;
+  String c0 = "r";
+  String c1 = "i";
+  passphrase.runes.forEach((int rune) {
+    c0 = c(o(c0) + o(c1) * alpha);
+    c1 = c(o(c1) + n(rune) * beta);
+  });
+  return c0 + c1;
+}
+
+void main() {
+//   "abcdefghijklmnopqrstuvwxyz".runes.forEach((int rune) {
+//     print('$rune : ${new String.fromCharCode(rune)} :: ${n(rune)} ${c(n(rune) + 28)}');
+//   });
+  
+//   for (var match in letters.allMatches('The quick ! broWn')) {
+//     print(match.group(0)); // 15, then 20
+//     };
+  
+//   print(letters.allMatches('The quick ! broWn').map((Match m) => m[0]).join());
+  
+  String phr = "the traveller in the grey riding-coat, who called himself mr. melville, was "
+                      "contemplating the malice of which the gods are capable.";
+  
+//  print(code1('the cat.'));
+  print(code1(phr));
+  
+//  print(code2('the cat.'));
+  print(code2(phr));
+}