Part I: Output the characters with their frequency
f(a)=5; 
f(b)=3; 
f(c)=4; 
f(d)=1; 
f(e)=2; 

Part II: Huffman tree is done. 
Part III: The old char can be represented by new code.
Characters---   New represent
b         ---   00
d         ---   010
e         ---   011
c         ---   10
a         ---   11
Compression factor: 3.63636