Add longest path algorithm.

lang/es/home.php

@@ -277,4 +277,7 @@ Tenemos traducciones en griego 🇬🇷.</a> <a href=\"https://github.com/UnickS
     $g_lang['other_algorithms'] = "Other algorithms";    
 
     $g_lang['use_context_menu'] = "Use context menu for additional actions.";
+
+    $g_lang['find_longest_path'] = "Find the longest path";
+    $g_lang['length_of_longest_path_from'] = "Length of the longest path from ";     
 ?>