import os,hashlib,shutil
md5dict={}
A=r"A"
B=r"B"
C=r"C"
for filename in os.listdir(A):
hashvalue=hashlib.md5(open(os.path.join(A,filename)).read()()).hexdigest()
md5dict[hashvalue]=os.path.join(A,filename)
for filename in os.listdir(B):
hashvalue=hashlib.md5(open(os.path.join(B,filename)).read()).hexdigest()
if hashvalue in md5dict:
shutil.copy(os.path.join(B,filename),os.path.join(C,filename))