Initial commit

2015/puzzle-05-01.cc

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+#include <algorithm>
+#include <cassert>
+#include <iostream>
+#include <set>
+#include <string>
+
+// Check if a string is nice:
+// Nice strings have:
+//  >=3 vowels
+//  At least one double letter
+//  No instances of 'ab', 'cd', 'pq', or 'xy'.
+bool is_nice(std::string const &s) noexcept {
+  unsigned vowel_count = 0;
+  bool repeated = false;
+  char last = '\0';
+
+  std::string vowels("aeiou");
+  for (auto c : s) {
+    if (vowels.find(c) != std::string::npos) {
+      ++vowel_count;
+    }
+    if (c == last) {
+      repeated = true;
+    }
+    if ((last == 'a' && c == 'b') || (last == 'c' && c == 'd') ||
+        (last == 'p' && c == 'q') || (last == 'x' && c == 'y')) {
+      return false;
+    }
+    last = c;
+  }
+
+  return repeated && vowel_count >= 3;
+}
+
+int main(int argc, char **argv) {
+  unsigned nice_strings;
+  for (std::string line; std::getline(std::cin, line);) {
+    nice_strings += is_nice(line);
+  }
+  std::cout << nice_strings << '\n';
+
+  return 0;
+}