Question

1. You went for a walk on a strange street and now you’re lost. There are N stores in a row on the street (1≤N≤100). Each store has a sign with a single letter in the range of A…Z (not required to be a unique letter per sign). You want to use the letters of the signs closest to you to help you figure out your location. The sequence of N signs along the street can be represented as a string of length N with letters in the range of A…Z.

What is the smallest value of M signs so that if you look at any sequence of M consecutive signs, you can uniquely figure out the location of that sequence along the street?

For example, if the sequence of signs is “IXMVDKIXMV,” M cannot be 3 because “IXM” is in two places; also, M cannot be 4 because “IXMV” is on the street in two places. M = 5 is the smallest set of signs because all sequences of 5 consecutive signs are unique.

Your function must have two inputs: The first one is an integer N. The second input is the string of N characters A…Z representing the signs along the street.

            Your function must output a single integer, M.

            Provide your Java code separately. What is the runtime of your algorithm?

Answer 1

import java.util.*;

public class SmallValueOfSigns {

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner sc=new Scanner(System.in);

int limit=0;

char[] ch=new char[100];

String signs=sc.nextLine();

int len=signs.length();

String str="";

for(int i=0;i<len;i++) {

  

str=str+signs.charAt(i);

String str2=signs.substring(i+1)

  

  

if(!(str2.contains(str))) {

  

limit=str.length();

  

break;

}

  

  

}

System.out.println(limit); //here we are printing smallest set of sequence which is M;

}

}

Explanation:

1.Here str is to take sequnce of given signs which is needed to check with given str2.

2.str2 is to take substring of given signs afterwards of the str which is needed to be checked with str1 whether it contains str or not.

3. If str2 not contains str it means that str is the smallest set of sequence so that we can break the loop and return the smallest set of sequence that is M(length of str)

Runtime:

Run time of this algarithm is O(n) beacuse it contains only one loop.

may this help you!!!!