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Problem solution · Java

CCC 2003 S4 - Substrings

CCC 2003 S4 - Substrings: a Java solution using direct simulation. Learn the idea, check the complexity, and read the full code, with credit to CCCSolutions.

Technique
Direct simulation
Source
CCCSolutions
Length
66 lines
Start with the idea.

Try the problem first. If you get stuck, read the approach below, then write your own solution. The full code is at the bottom.

Approach

Direct simulation

For CCC 2003 S4 - Substrings, the implementation follows the problem’s operations directly while maintaining only the state needed for the next decision.

  1. Translate each rule into one explicit state update.
  2. Maintain the invariant after every processed item.
  3. Return the accumulated state once all relevant input has been handled.

Code notes

  • 66 lines of Java from the credited upstream file ccc03s4.java.
  • The implementation visibly relies on sequence storage.
  • 3 loop blocks detected.

Complexity

Count the number and nesting of passes over the input, then include the maintained containers in the memory estimate.

Check the problem constraints before deciding whether this complexity will pass.

Source

Code and credit

This code comes from CCCSolutions by CCCSolutions contributors · Milliken Mills High School and is used under the MIT licence.

Open problem ↗Original source ↗
Full codeCCC 2003 S4 - Substrings · JavaJava
Use this to learn the idea, then write your own version.
// CCC 2003// Problem S4 Substrings//// given a string, determine the number of DISTINCT substrings// the empty string and the full string are counted.//// this involves taking each possible substring and// checking if it is a duplicate.//// algorithm is:// for each possible substring://   if the substring is found where you created it, it's not a dup.//   else if that substring occurs earlier in the string it is a dup.//// this observation is due to Vassili Skarine, Northview Heights SS//// file input: number of strings and the strings themselves// output the # of distinct substrings import java.awt.*;import hsa.*; public class S4SubstringsVS{    static Console cc;    //    static String [] sub;    //    static int ns;     public static void main (String[] args)    {	cc = new Console (); 	String s, t;	int n;	int total = 0;	TextInputFile fi = new TextInputFile ("substr3.in");	TextOutputFile fo = new TextOutputFile ("substr3.out"); 	n = fi.readInt (); 	for (int i = 0 ; i < n ; i++)	{	    // read the string	    s = fi.readLine ();	    total = 2; 	    // for each different length	    for (int k = 1 ; k < s.length () ; k++)	    {		for (int j = 0 ; j <= s.length () - k ; j++)		{		    t = s.substring (j, j + k);		    // if found where it was created, not a dup		    // otherwise a dup: don't count it.		    if (s.indexOf (t) == j)			total++;		}	    }	    fo.println (total);	    cc.println (total);	}	fi.close ();	fo.close ();    }}

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