[OT] The horizon of a stream

[mgen]

If size is a problem use a trie!

//---CODE---
import std.stream;
import std.stdio;

class position_trie
{
bool seen = false;
int last_seen = 0;
position_trie[char] branch;
}

void main()
{
  int[char[]] last;
  int max;
  Stream file = new MemoryStream(
    "lorem
ipsum
dolor
habeas
corpus
ipsum
sit
amet
rigor
mortis
consectetur
coitus
interruptus
corpus
adipisicing
elit"
  );
  auto root = new position_trie();
  position_trie node = root;
  position_trie next;
  foreach(ulong lineno,char[] line;file)
  {
    foreach(int chrno,char chr;line)
    {
      if(chr in node.branch)
      {
        node = node.branch[chr];
      }
      else
      {
        next = new position_trie();
        node.branch[chr] = next;
        node = next;
        foreach(char chr2; line[chrno+1..$])
        {
          next = new position_trie();
          node.branch[chr2] = next;
          node = next;
        }
        break;
      }
    }
    if(node.seen)
    {
      auto dist = lineno - node.last_seen;
      if(dist > max)
        max = dist;
    }
    node.seen = true;
    node.last_seen = lineno;
    node = root;
  }
  writefln(max);
}