<div>
The instructions say you have to do this challenge recursively. 
What would happen if you modified your code to just call replace without all those if statements?
</div>

<div>
No recursion is necessary for this challenge. You could just use 
<a href="http://docs.oracle.com/javase/8/docs/api/java/lang/String.html#replaceAll-java.lang.String-java.lang.String-" rel="ugc">http://docs.oracle.com/javase/8/docs/api/java/lang/String.html#replaceAll-java.lang.String-java.lang.String-</a>
</div>

<div>
&gt;&gt; No recursion is necessary for this challenge. 
You are already stating what the author has observed. 
But the challenge is to learn how to use recursion.
</div>

<div>
@phoffric, &nbsp;gudii9 has already gone through 11 recursion challenges last week. &nbsp;He will not learn anything by using recursion when it is not useful. &nbsp;He really needs to learn the API better.
</div>

<div>
I'm sorry. I was wrong. &nbsp; Your choice of the replace method is fine.
</div>

<div>
&gt;&gt; I'm sorry. I was wrong. &nbsp; Your choice of the replace method is fine. 
Could you elaborate on the meaning of this? 
 
Are you saying that the author's solution is fine by using the replace method? 
I have the same question where you wrote this in two other questions from this author.
</div>

<div>
@phoffric, I just meant that my previous suggestion was not helpful.
</div>

<div>
<pre><code class="code-10 nolinks" id="code-20-41804116-1">public String noX(String str) {
 // public String changeXY(String str) {
 if (str.length() == 0){ 
 return str;
 
 }
 else if (str.charAt(0) == 'x') {
 return &quot;&quot; + noX(str.substring(1));
 
 }
 else{ 
 return str.charAt(0) + noX(str.substring(1));
 
 }
}
</code></pre>
 
above passes all tests, 
 
any improvement or alternate approaches?
</div>

<div>
In this question and in others, it looks like you all are recursively examining one char at a time. If the string is 10 thousand chars long, then the stack will have 10000 frames. 
 
How about doing a find operation in noX? 
<a href="http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#indexOf%28int%29" rel="ugc">http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#indexOf%28int%29</a> 
Then, if there are only 1% of the undesired char, the stack will only have 100 frames.
</div>

<div>
@phoffric, I have already demonstrated the use of indexOf &nbsp;at &nbsp; 
<a href="https://www.experts-exchange.com/questions/28970071/changeXy-challenge.html?anchorAnswerId=41804107#a41804107" rel="ugc">https://www.experts-exchange.com/questions/28970071/changeXy-challenge.html?anchorAnswerId=41804107#a41804107</a>&nbsp; &nbsp; 
and &nbsp; 
<a href="https://www.experts-exchange.com/questions/28968901/countHi-challenge.html?anchorAnswerId=41797015#a41797015" rel="ugc">https://www.experts-exchange.com/questions/28968901/countHi-challenge.html?anchorAnswerId=41797015#a41797015</a>&nbsp; &nbsp; 
and &nbsp; &nbsp; 
<a href="https://www.experts-exchange.com/questions/28968900/countX.html?anchorAnswerId=41796932#a41796932" rel="ugc">https://www.experts-exchange.com/questions/28968900/countX.html?anchorAnswerId=41796932#a41796932</a>
</div>

<div>
not clear on above comments. are we saying not to use recursion if more characters to check?
</div>

<div>
@rrz, 
I am unclear why you are identifying posts in other questions. Are you asking me to read them and verify them? Or what?
</div>

<div>
@phoffric and gudii9, I posted those three links to show examples of where I used indexOf in recent challenges. The same approach I used in those examples, can be used in this challenge.
</div>

<div>
<pre><code class="code-10 nolinks" id="code-20-41807420-1">public String noX(String str) {
 // public String changeXY(String str) {
 if(&quot;&quot;.equals(str)){
 return &quot;&quot;;
 }
 else if (str.charAt(0) == 'x') {
 return &quot;&quot; + noX(str.substring(1));
 
 }
 else{ 
 return str.charAt(0) + noX(str.substring(1));
 
 }
}
 /* public String noX(String str) {
 if (&quot;&quot;.equals(str)){ 
 return &quot;&quot;;
 }
 if (str.charAt(0) == 'x') {
 return noX(str.substring(1));
 }
 return str.charAt(0) + noX(str.substring(1));
}
 
 A*/
/* public String changePi(String str) {
 if (str.equals(&quot;&quot;) || str.length() &lt; 2) return str;
 if (str.charAt(0) == 'p' &amp;&amp; str.charAt(1) == 'i') 
 return &quot;3.14&quot; + changePi(str.substring(2));
 return str.charAt(0) + changePi(str.substring(1));
}*/
</code></pre>
above passes all
</div>

<div>
<div class="content wysiwyg-content">
Hi, 
 
I am working on below challenge 
<a href="http://codingbat.com/prob/p118230" rel="ugc">http://codingbat.com/prob/p118230</a> 
 
Psedo code: 
1. if array length is zero return &quot;&quot; 
2. if array length is 1 and it is x return &quot;&quot; 
3. if array length is 1 and it is not x return same str 
4. else find location of x and replace with &quot;&quot;&nbsp;if greater than length 
5. return replaced string 
 

<pre><code class="code-10 nolinks" id="code-10-28970078-1">public String noX(String str) {
 if(str.length()==0){
 return &quot;&quot;;
 }
 if(str.length()==1&amp;&amp;&quot;x&quot;.equals(str)){
 return &quot;&quot;;
 }
 if(str.length()==1&amp;&amp;!&quot;x&quot;.equals(str)){
 return str;
 }
 if(str.length()&gt;1){
 return str.replace(&quot;x&quot;,&quot;&quot;);
 }
 
 
 return null;
}
</code></pre>
 
 
 
I am passing all tests 
 
How to improve/modify my design, code and any other alternate approaches. please advise
</div>
</div>

Hi,

I am working on below challenge
http://codingbat.com/prob/p118230

Psedo code:
1. if array length is zero return ""
2. if array length is 1 and it is x return ""
3. if array length is 1 and it is not x return same str
4. else find location of x and replace with "" if greater than length 
5. return replaced string

(CODE)



I am passing all tests

How to improve/modify my design, code and any other alternate approaches. please advise

noX challenge

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