title: Check if a string is available in a bigger string of length 100,000
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/3183582/what-is-the-fastest-substring-search-algorithm">What is the fastest substring search algorithm?</a>  </p>
  </blockquote>
  
  
  
  <p>How do I check if a string is present in a bigger string of length of 100,000 characters in C++ or Java?</p>
  
  <p>I know a method <code>str.find("sub_string");</code> but it can't  handle such a big string. 
  The max execution time is 1 sec.</p>
  
  <p>Also the sub strings I need to look for can be 50,000!</p>