[Last Call] Learn about multicloud storage options and how to improve your company's cloud strategy. Register Now

x
?
Solved

count11 challenge

Posted on 2016-09-21
6
Medium Priority
?
120 Views
Last Modified: 2016-09-22
Hi,

I am working on below challenge.
http://codingbat.com/prob/p167015
Psedo code:
1. check the array length 0  or 1 then retun 0
2.else if string does not consist of 11  return 0
3.else increment by 1 and calling same recursion function

I wrote my code as below and not passing all tests

public int count11(String str) {
  
  
  
 CharSequence cs1="11";
 
 //CharSequence cs2="aba";
  if(str.length()==0||str.length()==1||str.length()==2){
    return 0;
  }


  else if(!str.contains(cs1)){
    return 0;
  }
  else return 1+count11(str.substring(1));

}

Open in new window


Expected      Run            
count11("11abc11") → 2      5      X      
count11("abc11x11x11") → 3      9      X      
count11("111") → 1      1      OK      
count11("1111") → 2      2      OK      
count11("1") → 0      0      OK      
count11("") → 0      0      OK      
count11("hi") → 0      0      OK      
count11("11x111x1111") → 4      9      X      
count11("1x111") → 1      3      X      
count11("1Hello1") → 0      0      OK      
count11("Hello") → 0      0      OK      
other tests
X      

Any improvements or alternate approaches?      

please advise
0
Comment
Question by:gudii9
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
6 Comments
 
LVL 37

Accepted Solution

by:
zzynx earned 2000 total points
ID: 41810180
This works

public int count11(String str) {
  String string11 = "11";
 
  if(str.length()==0||str.length()==1){
    return 0;
  }

  if(str.startsWith(string11)){
     return 1 + count11(str.substring(2));
  }
  return count11(str.substring(1));
}

Open in new window

0
 
LVL 7

Author Comment

by:gudii9
ID: 41810814
how contains different from startsWith method?
why cannot i use contains method here?
public int count11(String str) {
  
  
  
 CharSequence cs1="11";
 
 //CharSequence cs2="aba";
  if(str.length()<3){
    return 0;
  }


  else if(!str.contains(cs1)){
    return 0;
  }
  else return 1+count11(str.substring(2));

}

Open in new window


below also fails?
0
 
LVL 7

Author Comment

by:gudii9
ID: 41810929
public int count11(String str) {
  String string11 = "11";
 
  if(str.length()==0||str.length()==1){
    return 0;
  }

  if(str.startsWith(string11)){
     return 1 + count11(str.substring(2));
  }
  return count11(str.substring(1));
}

Open in new window


i like above approach checking if string 11 there then increment by 1 and shift two positions(as duplicats not needed) and call same recursion method
0
Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

 
LVL 37

Expert Comment

by:zzynx
ID: 41810962
>> i like above approach
OK. Good. :)

Again, you can of course replace
if(str.length()==0||str.length()==1){
    return 0;
}

Open in new window

by
if(str.length()<2){
    return 0;
}

Open in new window


>> why cannot i use contains method
contains() versus startsWith()
The answer is in their names.
0
 
LVL 7

Author Comment

by:gudii9
ID: 41811219
>> why cannot i use contains method
contains() versus startsWith()
The answer is in their names.

can you please elaborate.

one to check if starts with a string
other if contains only charactersequence?
0
 
LVL 37

Expert Comment

by:zzynx
ID: 41811979
Starting with a certain string
or
containing a certain string
are two different things.
In this case of recurrence you really need the first one
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Having just graduated from college and entered the workforce, I don’t find myself always using the tools and programs I grew accustomed to over the past four years. However, there is one program I continually find myself reverting back to…R.   So …
Introduction This article is the last of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article covers our test design approach and then goes through a simple test case example, how …
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.
How to fix incompatible JVM issue while installing Eclipse While installing Eclipse in windows, got one error like above and unable to proceed with the installation. This video describes how to successfully install Eclipse. How to solve incompa…

650 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question