diff --git a/2018/solutions/prob12.cpp b/2018/solutions/prob12.cpp
index 9c483ea..6fa9774 100644
--- a/2018/solutions/prob12.cpp
+++ b/2018/solutions/prob12.cpp
@@ -4,27 +4,16 @@
 
 int main() {
   bool valid = true;
-  std::string line;
-  std::vector<std::string> words;
-  size_t wordsLength, halfWordsLength;
+  std::string line, full;
+  size_t i, j;
 
   while (std::cin >> line) {
-    words.push_back(line);
+    full.append(line);
   }
 
-  wordsLength = words.size() - 1;
-  halfWordsLength = wordsLength / 2;
-  for (size_t i = 0; i <= halfWordsLength; i++) {
-    for (size_t j = 0; j <= halfWordsLength; j++) {
-      if (words[i][j] != words[j][i])
-        valid = false;
-
-      if (words[i][j] != words[wordsLength - i][wordsLength - j])
-        valid = false;
-
-      if (words[i][j] != words[wordsLength - j][wordsLength - i])
-        valid = false;
-    }
+  for (i = full.size() - 1, j = 0; i > 0; i--, j++) {
+    if (full[i] != full[j])
+      valid = false;
   }
 
   std::cout << ((valid) ? "TRUE" : "FALSE") << std::endl;