add huffman tree generator

Author: trashw1n

huffmantree.py

@@ -0,0 +1,25 @@
+Python 3.10.0 (tags/v3.10.0:b494f59, Oct  4 2021, 19:00:18) [MSC v.1929 64 bit (AMD64)] on win32
+Type "help", "copyright", "credits" or "license()" for more information.
+from heapq import heapify as hpf
+from heapq import heappop as hpp
+from heapq import heappush as hppu
+class Node:
+    def __init(self,ch,freq,left=None,right=None):
+        self.ch,self.freq=ch,freq
+        self.left,self.right=left,right
+    def __lt__(self,other):
+        return self.freq<other.freq
+
+def getHuffmanTree(txt):
+    if len(txt)==0:
+        return
+    freq={ch:text.count(ch) for k,v in set(txt)}
+    pq=[Node(k,v) for k,v in freq.items()]
+    hpf(pq)
+    while len(pq)>1:
+        left,right=hpp(pq),hpp(pq);
+        newFreq=left.freq+right.freq
+        hppu(pq,Node(None,newFreq,left,right))
+    root=pq[0]
+    return root
+