How to construct Huffman Tree from preorder scan?












0














I'm a little confused about how to build a Huffman tree from a preorder scan. I encoded my header similar to how it was explained here



But I'm not entirely sure how to read the scan and build the tree, my scan looks like this



01a001c1b001f1e1d# (the hashtag is for breaking out of the loop)



This is my attempt to build the tree, though it's not quite right



 HuffmanNode rootTest=new HuffmanNode((byte)preOrderString.charAt(0));
Stack<HuffmanNode> s = new Stack<HuffmanNode>();
HuffmanNode current=rootTest;
root=current;
s.push(current);
for(int i=1;i<preOrderString.length();i++) {
if(preOrderString.charAt(i)=='0') {
HuffmanNode next=new HuffmanNode((byte)preOrderString.charAt(i));
if(current.left==null)
current.left=next;
else
current.right=next;
current=next;
System.out.println(current);
s.push(current);
}
if(preOrderString.charAt(i)=='1') {
i++;
if(current.left==null) {
current.left=new HuffmanNode((byte)preOrderString.charAt(i));
System.out.println("left "+current.left);
}
else if(current.right==null){
current.right=new HuffmanNode((byte)preOrderString.charAt(i));
System.out.println("right "+current.right);
}
while(!s.isEmpty()) {
current=s.pop();
}
}
}









share|improve this question





























    0














    I'm a little confused about how to build a Huffman tree from a preorder scan. I encoded my header similar to how it was explained here



    But I'm not entirely sure how to read the scan and build the tree, my scan looks like this



    01a001c1b001f1e1d# (the hashtag is for breaking out of the loop)



    This is my attempt to build the tree, though it's not quite right



     HuffmanNode rootTest=new HuffmanNode((byte)preOrderString.charAt(0));
    Stack<HuffmanNode> s = new Stack<HuffmanNode>();
    HuffmanNode current=rootTest;
    root=current;
    s.push(current);
    for(int i=1;i<preOrderString.length();i++) {
    if(preOrderString.charAt(i)=='0') {
    HuffmanNode next=new HuffmanNode((byte)preOrderString.charAt(i));
    if(current.left==null)
    current.left=next;
    else
    current.right=next;
    current=next;
    System.out.println(current);
    s.push(current);
    }
    if(preOrderString.charAt(i)=='1') {
    i++;
    if(current.left==null) {
    current.left=new HuffmanNode((byte)preOrderString.charAt(i));
    System.out.println("left "+current.left);
    }
    else if(current.right==null){
    current.right=new HuffmanNode((byte)preOrderString.charAt(i));
    System.out.println("right "+current.right);
    }
    while(!s.isEmpty()) {
    current=s.pop();
    }
    }
    }









    share|improve this question



























      0












      0








      0







      I'm a little confused about how to build a Huffman tree from a preorder scan. I encoded my header similar to how it was explained here



      But I'm not entirely sure how to read the scan and build the tree, my scan looks like this



      01a001c1b001f1e1d# (the hashtag is for breaking out of the loop)



      This is my attempt to build the tree, though it's not quite right



       HuffmanNode rootTest=new HuffmanNode((byte)preOrderString.charAt(0));
      Stack<HuffmanNode> s = new Stack<HuffmanNode>();
      HuffmanNode current=rootTest;
      root=current;
      s.push(current);
      for(int i=1;i<preOrderString.length();i++) {
      if(preOrderString.charAt(i)=='0') {
      HuffmanNode next=new HuffmanNode((byte)preOrderString.charAt(i));
      if(current.left==null)
      current.left=next;
      else
      current.right=next;
      current=next;
      System.out.println(current);
      s.push(current);
      }
      if(preOrderString.charAt(i)=='1') {
      i++;
      if(current.left==null) {
      current.left=new HuffmanNode((byte)preOrderString.charAt(i));
      System.out.println("left "+current.left);
      }
      else if(current.right==null){
      current.right=new HuffmanNode((byte)preOrderString.charAt(i));
      System.out.println("right "+current.right);
      }
      while(!s.isEmpty()) {
      current=s.pop();
      }
      }
      }









      share|improve this question















      I'm a little confused about how to build a Huffman tree from a preorder scan. I encoded my header similar to how it was explained here



      But I'm not entirely sure how to read the scan and build the tree, my scan looks like this



      01a001c1b001f1e1d# (the hashtag is for breaking out of the loop)



      This is my attempt to build the tree, though it's not quite right



       HuffmanNode rootTest=new HuffmanNode((byte)preOrderString.charAt(0));
      Stack<HuffmanNode> s = new Stack<HuffmanNode>();
      HuffmanNode current=rootTest;
      root=current;
      s.push(current);
      for(int i=1;i<preOrderString.length();i++) {
      if(preOrderString.charAt(i)=='0') {
      HuffmanNode next=new HuffmanNode((byte)preOrderString.charAt(i));
      if(current.left==null)
      current.left=next;
      else
      current.right=next;
      current=next;
      System.out.println(current);
      s.push(current);
      }
      if(preOrderString.charAt(i)=='1') {
      i++;
      if(current.left==null) {
      current.left=new HuffmanNode((byte)preOrderString.charAt(i));
      System.out.println("left "+current.left);
      }
      else if(current.right==null){
      current.right=new HuffmanNode((byte)preOrderString.charAt(i));
      System.out.println("right "+current.right);
      }
      while(!s.isEmpty()) {
      current=s.pop();
      }
      }
      }






      java huffman-code






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      edited Nov 12 '18 at 17:07

























      asked Nov 12 '18 at 7:55









      TheHaruWhoCodes

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