TRIE DATA STRUCTURES

Question

Can anybody please help me verify my code. I tried writing this code and it works properly, since I am new to this coding, I am not having confidence that I have written the correct logic and I am dependent on others to check whether I am right.
Thank you in advance.

public class TrieNode {
HashMap<Character, TrieNode> map = new HashMap<Character, TrieNode>();
TrieNode root;
TrieNode temp;

public TrieNode() {
this.root = null;

}

String End = "N";

public void insert(String element) {
TrieNode node = new TrieNode();
if (root == null) {
root = node;
} else {
node = root;
}
for (int i = 0; i <= element.length(); i++) {
if (i < element.length()) {
if (!node.map.containsKey(element.charAt(i))) {
temp = new TrieNode();
node.map.put(element.charAt(i), temp);
node = temp;
} else {
node = node.map.get(element.charAt(i));
}
} else {
node.End = "Y";
}

}
}

public boolean search(String element) {
TrieNode node = new TrieNode();
node = root;
if (root == null) {
System.out.println("Trie empty");
return false;
} else {
for (int i = 0; i <= element.length(); i++) {
if (i < element.length() && node.map.containsKey(element.charAt(i))) {
node = node.map.get(element.charAt(i));
} else if (i == element.length() && node.End == "Y") {
System.out.println("Word found");
return true;
} else {
System.out.println("Word not found");
return false;
}

}
return true;
}
}

}

Answer 1

@Ronaldo Pi Ma Si ,
Got it ,. Thank you so much for suggesting and I never thought of boolean, that's why used String,
Undoubtedly your reply helped me .
Thank you again for checking my code.

Answer 2

Ronaldo Pi Ma Si
I have a doubt sir,
In Insert, if I try to insert AIR,then it will be insert as A(End : False ) -> I (End : False )-> R(End : True )
1.Correct me if I am wrong?

2.But in search for loop,
We check for A -> I -> R and its present, but we should check the end of node for R as true to return true,

3.Can you also please clarify what is the meaning of "else if !(node.End)" ?

Answer 3

yes that is needed in logic to add true at the last alphabet.

No need to tell sorry, I should thank you for checking my code.

Wish I should gain confidence.:)

Answer 4

Seems to be working. But is it needed using property "End" as String? - I would try boolean;

The loop for, for (int i = 0; i < element.length(); i++) - I would use "< " without if (i < length) later;

What do you think about, did I help? @Divya Dharshini

public class TrieNode {
boolean End = false;
HashMap<Character, TrieNode> map = new HashMap<Character, TrieNode>();
TrieNode root;
TrieNode temp;

public TrieNode() {
this.root = null;
}

public void insert(String element) {
TrieNode node = new TrieNode();
if (root == null) {
root = node;
} else {
node = root;
}

for (int i = 0; i < element.length(); i++) {
if (!node.map.containsKey(element.charAt(i))) {
temp = new TrieNode();
node.map.put(element.charAt(i), temp);
node = temp;
} else {
node = node.map.get(element.charAt(i));
}
} // loop for ends here.

node.End = true;
}

public boolean search(String element) {
TrieNode node = new TrieNode();
node = root;
if (root == null) {
System.out.println("Trie empty");
return false;
} else {
for (int i = 0; i < element.length(); i++) {
if (node.map.containsKey(element.charAt(i))) {
node = node.map.get(element.charAt(i));
System.out.println("Word found");
return true;
} else {
System.out.println("Word not found");
return false;
}

}
return true;
}
}

}

Answer 5

Hello @Divya Dharshini.

Yes. ... -> R(End : True )... // aways in the end of insert the (object.property) node.End will be set true. Because I understand this is expected., Is that correct?

And... "else if !(node.End)" ... Sorry, it is not needed. I am gonna EDITING my code.

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Hi @Divya Dharshini, sorry so much, my suggestions are wrong.

How you could see You are good enough, believe yourself. "I am not having confidence that I have written the correct logic..." But you could point out the errors in my code.